[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_ring_routing
Scenario ID: retail_f7_ring_routing_v4

[BUSINESS DESCRIPTION]
Business narrative:
Locations are connected in a directed ring, mimicking a truck route that visits each location in a fixed cycle. Inventory can only move along the ring edges, and storage capacities are tightened so that the chosen routing structure affects feasibility and cost. Demand is local and exogenous at each node, and unmet demand is lost and penalized.

Structure cues:
- The transshipment network in the JSON forms a directed cycle: DC1->DC2->DC3->DC4->DC5->DC1. Inventory can be shipped only along these ring edges.
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. Capacities are scaled to 80% of normal values.
- For each product, location, and period, inventory reflects previous stock, local production, inbound ring shipments, outbound ring shipments, sales, and waste, and must remain non-negative.
- Demand at each location is met from local inventory and inbound ring shipments; there are no shortcuts across the ring.
- Inventory that moves further along the route must pass through intermediate locations in sequence.
- Lead times for ring shipments are effectively zero in this archetype, and substitution behavior is as encoded.
- The objective is to minimize total cost (aggregating purchasing, holding, waste, lost sales, and transshipment costs) while respecting the ring network structure and tighter storage capacities.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_ring_routing
Scenario ID: retail_f7_ring_routing_v4

[BUSINESS DESCRIPTION]
Business narrative:
Locations are connected in a directed ring, mimicking a truck route that visits each location in a fixed cycle. Inventory can only move along the ring edges, and storage capacities are tightened so that the chosen routing structure affects feasibility and cost. Demand is local and exogenous at each node, and unmet demand is lost and penalized.

Structure cues:
- The transshipment network in the JSON forms a directed cycle: DC1->DC2->DC3->DC4->DC5->DC1. Inventory can be shipped only along these ring edges.
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. Capacities are scaled to 80% of normal values.
- For each product, location, and period, inventory reflects previous stock, local production, inbound ring shipments, outbound ring shipments, sales, and waste, and must remain non-negative.
- Demand at each location is met from local inventory and inbound ring shipments; there are no shortcuts across the ring.
- Inventory that moves further along the route must pass through intermediate locations in sequence.
- Lead times for ring shipments are effectively zero in this archetype, and substitution behavior is as encoded.
- The objective is to minimize total cost (aggregating purchasing, holding, waste, lost sales, and transshipment costs) while respecting the ring network structure and tighter storage capacities.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_ring_routing_v4",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 3070.401666288584,
    "DC2": 2912.4256523689965,
    "DC3": 2222.094000824833,
    "DC4": 2372.7145024774154,
    "DC5": 1839.1810420730599
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      333,
      332,
      303,
      364,
      376,
      620,
      734,
      972,
      1246,
      1404,
      1159,
      1189,
      1052,
      936,
      756,
      560,
      389,
      372,
      337,
      356
    ],
    "SKU_Premium": [
      168,
      176,
      172,
      167,
      204,
      261,
      349,
      461,
      521,
      669,
      620,
      562,
      480,
      385,
      337,
      279,
      216,
      189,
      174,
      170
    ],
    "SKU_ShortLife": [
      138,
      120,
      123,
      154,
      191,
      214,
      313,
      330,
      487,
      517,
      554,
      561,
      420,
      320,
      293,
      192,
      150,
      126,
      135,
      121
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.


[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v0

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v0

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_transshipment_v0",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 4000,
    "DC2": 3500,
    "DC3": 3000,
    "DC4": 3000,
    "DC5": 2500
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      303,
      311,
      328,
      365,
      435,
      549,
      711,
      906,
      1100,
      1245,
      1300,
      1245,
      1100,
      906,
      711,
      549,
      435,
      365,
      328,
      311
    ],
    "SKU_Premium": [
      151,
      155,
      164,
      182,
      217,
      274,
      355,
      453,
      550,
      622,
      650,
      622,
      550,
      453,
      355,
      274,
      217,
      182,
      164,
      155
    ],
    "SKU_ShortLife": [
      121,
      124,
      131,
      146,
      174,
      219,
      284,
      362,
      440,
      498,
      520,
      498,
      440,
      362,
      284,
      219,
      174,
      146,
      131,
      124
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC1",
        "DC3"
      ],
      [
        "DC1",
        "DC4"
      ],
      [
        "DC1",
        "DC5"
      ],
      [
        "DC2",
        "DC1"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC2",
        "DC4"
      ],
      [
        "DC2",
        "DC5"
      ],
      [
        "DC3",
        "DC1"
      ],
      [
        "DC3",
        "DC2"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC3",
        "DC5"
      ],
      [
        "DC4",
        "DC1"
      ],
      [
        "DC4",
        "DC2"
      ],
      [
        "DC4",
        "DC3"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ],
      [
        "DC5",
        "DC2"
      ],
      [
        "DC5",
        "DC3"
      ],
      [
        "DC5",
        "DC4"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.


[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v1

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v1

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_transshipment_v1",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 4350.379022623083,
    "DC2": 4021.4850768661436,
    "DC3": 2722.064202033501,
    "DC4": 3099.4558270405596,
    "DC5": 2284.624833727947
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      346,
      298,
      303,
      409,
      442,
      505,
      724,
      1015,
      956,
      1059,
      1169,
      1086,
      1019,
      867,
      769,
      545,
      382,
      342,
      306,
      285
    ],
    "SKU_Premium": [
      131,
      161,
      187,
      190,
      185,
      290,
      375,
      400,
      508,
      693,
      576,
      670,
      482,
      471,
      310,
      238,
      223,
      176,
      149,
      160
    ],
    "SKU_ShortLife": [
      134,
      127,
      145,
      124,
      185,
      231,
      280,
      370,
      420,
      525,
      518,
      557,
      470,
      380,
      308,
      231,
      180,
      146,
      124,
      115
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC1",
        "DC3"
      ],
      [
        "DC1",
        "DC4"
      ],
      [
        "DC1",
        "DC5"
      ],
      [
        "DC2",
        "DC1"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC2",
        "DC4"
      ],
      [
        "DC2",
        "DC5"
      ],
      [
        "DC3",
        "DC1"
      ],
      [
        "DC3",
        "DC2"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC3",
        "DC5"
      ],
      [
        "DC4",
        "DC1"
      ],
      [
        "DC4",
        "DC2"
      ],
      [
        "DC4",
        "DC3"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ],
      [
        "DC5",
        "DC2"
      ],
      [
        "DC5",
        "DC3"
      ],
      [
        "DC5",
        "DC4"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.


[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v2

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v2

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_transshipment_v2",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 4285.991673328941,
    "DC2": 3618.6622567015015,
    "DC3": 2927.394970495998,
    "DC4": 3260.5659553845603,
    "DC5": 2489.40749898572
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      314,
      273,
      309,
      404,
      485,
      598,
      760,
      820,
      1161,
      1358,
      1378,
      1060,
      1054,
      874,
      758,
      596,
      433,
      325,
      347,
      307
    ],
    "SKU_Premium": [
      139,
      156,
      176,
      172,
      226,
      313,
      377,
      505,
      571,
      702,
      631,
      628,
      565,
      430,
      399,
      275,
      204,
      171,
      163,
      133
    ],
    "SKU_ShortLife": [
      126,
      122,
      122,
      161,
      167,
      221,
      280,
      400,
      472,
      512,
      583,
      492,
      429,
      367,
      269,
      225,
      149,
      159,
      147,
      119
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC1",
        "DC3"
      ],
      [
        "DC1",
        "DC4"
      ],
      [
        "DC1",
        "DC5"
      ],
      [
        "DC2",
        "DC1"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC2",
        "DC4"
      ],
      [
        "DC2",
        "DC5"
      ],
      [
        "DC3",
        "DC1"
      ],
      [
        "DC3",
        "DC2"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC3",
        "DC5"
      ],
      [
        "DC4",
        "DC1"
      ],
      [
        "DC4",
        "DC2"
      ],
      [
        "DC4",
        "DC3"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ],
      [
        "DC5",
        "DC2"
      ],
      [
        "DC5",
        "DC3"
      ],
      [
        "DC5",
        "DC4"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.


[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v3

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v3

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_transshipment_v3",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 4013.8626163637355,
    "DC2": 3484.8019383571614,
    "DC3": 3037.478329781149,
    "DC4": 3425.155086535567,
    "DC5": 2394.032525917858
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      272,
      318,
      285,
      338,
      441,
      598,
      759,
      782,
      1120,
      1319,
      1395,
      1199,
      1149,
      849,
      751,
      553,
      490,
      356,
      286,
      305
    ],
    "SKU_Premium": [
      130,
      162,
      157,
      193,
      214,
      270,
      341,
      505,
      628,
      596,
      583,
      613,
      567,
      481,
      347,
      266,
      225,
      164,
      179,
      148
    ],
    "SKU_ShortLife": [
      121,
      107,
      139,
      161,
      183,
      199,
      310,
      366,
      409,
      452,
      581,
      555,
      459,
      318,
      264,
      240,
      174,
      138,
      148,
      116
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC1",
        "DC3"
      ],
      [
        "DC1",
        "DC4"
      ],
      [
        "DC1",
        "DC5"
      ],
      [
        "DC2",
        "DC1"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC2",
        "DC4"
      ],
      [
        "DC2",
        "DC5"
      ],
      [
        "DC3",
        "DC1"
      ],
      [
        "DC3",
        "DC2"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC3",
        "DC5"
      ],
      [
        "DC4",
        "DC1"
      ],
      [
        "DC4",
        "DC2"
      ],
      [
        "DC4",
        "DC3"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ],
      [
        "DC5",
        "DC2"
      ],
      [
        "DC5",
        "DC3"
      ],
      [
        "DC5",
        "DC4"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.


[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v4

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA SCHEMA]
{
  "name": str,                          # scenario identifier
  "periods": int,                       # number of time periods
  "products": [str, ...],               # list of product IDs
  "locations": [str, ...],              # list of location IDs

  "shelf_life": {p: int},               # shelf life in periods per product
  "lead_time": {p: int},                # order lead time per product (0 = same-period arrival)

  "demand_curve": {p: [float, ...]},    # demand per product per period (0-indexed list)
  "demand_share": {l: float},           # fraction of total demand at each location

  "production_cap": {p: [float, ...]},  # max production per product per period (0-indexed list)
  "cold_capacity": {l: float},          # storage capacity per location
  "cold_usage": {p: float},             # storage units per unit of product

  "labor_cap": {l: [float, ...]},       # labor hours per location per period (0-indexed list)
  "labor_usage": {p: float},            # labor hours per unit sold
  "return_rate": {p: float},            # fraction of sales returned next period

  "costs": {
    "purchasing": {p: float},           # cost per unit ordered
    "inventory": {p: float},            # holding cost per unit per period
    "waste": {p: float},                # cost per unit expired
    "lost_sales": {p: float},           # penalty per unit of unmet demand
    "fixed_order": float,               # fixed cost per order placed
    "transshipment": float              # cost per unit transshipped
  },

  "constraints": {
    "moq": float,                       # minimum order quantity (0 = no MOQ)
    "pack_size": int,                   # order must be multiple of this (1 = no constraint)
    "budget_per_period": float|null,    # max purchasing cost per period
    "waste_limit_pct": float|null       # max waste as fraction of total demand
  },

  "network": {
    "sub_edges": [[p_from, p_to], ...], # substitution: p_from's demand can be served by p_to
    "trans_edges": [[l_from, l_to], ...]# transshipment: can ship from l_from to l_to
  }
}

[DATA ACCESS]
- The variable `data` is pre-loaded. Do NOT use file I/O.
- Lists are 0-indexed (period t in model uses index [t-1] in data arrays)

CRITICAL - Network edges require tuple conversion for Gurobi:
  sub_edges = [tuple(e) for e in data.get('network', {}).get('sub_edges', [])]
  trans_edges = [tuple(e) for e in data.get('network', {}).get('trans_edges', [])]

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that models and solves this optimization problem.

[SCENARIO]
Family: F7 (Network and Multi Echelon)
Archetype: retail_f7_transshipment
Scenario ID: retail_f7_transshipment_v4

[BUSINESS DESCRIPTION]
Business narrative:
The retailer operates a fully connected lateral transshipment network among all locations. Inventory can be moved between any pair of locations at a transshipment cost, allowing local surpluses to be reallocated to locations facing shortages. Demand remains local and exogenous at each site, and unsatisfied demand after considering local stock and inbound transshipments is lost and penalized.

Structure cues:
- This archetype extends the single-echelon inventory model by allowing transshipment flows along directed edges given in the JSON; in this case, all ordered pairs of distinct locations are connected (full network).
- Shelf life: Each product has a shelf life in periods. Inventory must be tracked by REMAINING LIFE.

  VARIABLE DEFINITION: I[p,l,t,r] = inventory at START of period t with r periods remaining.
  Convention: r=1 is OLDEST (sell first FIFO), r=shelf_life[p] is FRESHEST.

  KEY EQUATIONS - implement EXACTLY as written, do NOT add or remove terms:

  (1) Fresh inflow: I[p,l,t,SL] = Q[p,t] * demand_share[l]
      - This is ONLY the inflow from production. Do NOT subtract sales here!
      - Q is total production, demand_share distributes it to locations.

  (2) Aging: I[p,l,t+1,r] = I[p,l,t,r+1] - sales[p,l,t,r+1] for r=1..SL-1
      - Inventory tomorrow with r remaining = inventory today with r+1 remaining - sales

  (3) Waste: W[p,l,t] = I[p,l,t,1] - sales[p,l,t,1]
      - Items with r=1 that aren't sold become waste

  (4) Sales availability: sales[p,l,t,r] <= I[p,l,t,r]
      - Can only sell what you have in inventory

  (5) Inventory holding cost: charged on (I[p,l,t,r] - sales[p,l,t,r]) for r >= 2
      - Charge on END-of-period inventory (after sales), exclude expiring items (r=1)
- Storage capacity: sum over products of (cold_usage[p] * total_inventory[p,l,t]) <= cold_capacity[l]. These limits must be respected at each location.
- For each product and period, inventory at a location changes according to incoming production, incoming transshipments, outgoing transshipments, sales, and waste, and must remain non-negative.
- Transshipment flows from a location in a period cannot exceed that location's available inventory for the product. All such moves incur transshipment costs as specified in the JSON.
- Demand remains local: each location's demand must be met from its own on-hand inventory and inbound transshipments, if available.
- Lead times for transshipment are effectively zero in this archetype, so shipments dispatched in a period are available at the destination within the same period.
- The objective is to minimize total cost including purchasing, holding, waste, lost sales, and transshipment costs.

[DATA]
The following JSON contains all instance data. Parse it directly in your code.

```json
{
  "name": "retail_f7_transshipment_v4",
  "description": "Standard seasonal retail scenario.",
  "periods": 20,
  "products": [
    "SKU_Basic",
    "SKU_Premium",
    "SKU_ShortLife"
  ],
  "locations": [
    "DC1",
    "DC2",
    "DC3",
    "DC4",
    "DC5"
  ],
  "shelf_life": {
    "SKU_Basic": 10,
    "SKU_Premium": 8,
    "SKU_ShortLife": 4
  },
  "lead_time": {
    "SKU_Basic": 0,
    "SKU_Premium": 0,
    "SKU_ShortLife": 0
  },
  "cold_capacity": {
    "DC1": 4358.239604043874,
    "DC2": 3435.3130461780443,
    "DC3": 3247.1030467862815,
    "DC4": 3369.300722713695,
    "DC5": 2795.7905924543456
  },
  "cold_usage": {
    "SKU_Basic": 1.0,
    "SKU_Premium": 3.0,
    "SKU_ShortLife": 1.2
  },
  "production_cap": {
    "SKU_Basic": [
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800,
      800
    ],
    "SKU_Premium": [
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400,
      400
    ],
    "SKU_ShortLife": [
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500,
      500
    ]
  },
  "labor_cap": {
    "DC1": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC2": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC3": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC4": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ],
    "DC5": [
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0,
      99999.0
    ]
  },
  "labor_usage": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "return_rate": {
    "SKU_Basic": 0.0,
    "SKU_Premium": 0.0,
    "SKU_ShortLife": 0.0
  },
  "demand_curve": {
    "SKU_Basic": [
      326,
      309,
      337,
      394,
      371,
      583,
      779,
      778,
      1058,
      1401,
      1471,
      1167,
      1155,
      944,
      621,
      618,
      413,
      417,
      343,
      302
    ],
    "SKU_Premium": [
      156,
      155,
      140,
      206,
      202,
      268,
      321,
      402,
      514,
      549,
      635,
      585,
      606,
      486,
      402,
      273,
      236,
      169,
      177,
      140
    ],
    "SKU_ShortLife": [
      113,
      122,
      127,
      167,
      157,
      249,
      320,
      367,
      489,
      521,
      548,
      527,
      383,
      388,
      302,
      243,
      193,
      129,
      129,
      133
    ]
  },
  "demand_share": {
    "DC1": 0.25,
    "DC2": 0.2,
    "DC3": 0.2,
    "DC4": 0.2,
    "DC5": 0.15
  },
  "costs": {
    "lost_sales": {
      "SKU_Basic": 50.0,
      "SKU_Premium": 80.0,
      "SKU_ShortLife": 40.0
    },
    "inventory": {
      "SKU_Basic": 1.0,
      "SKU_Premium": 1.5,
      "SKU_ShortLife": 1.0
    },
    "waste": {
      "SKU_Basic": 2.0,
      "SKU_Premium": 3.0,
      "SKU_ShortLife": 2.0
    },
    "fixed_order": 0.0,
    "transshipment": 0.5,
    "purchasing": {
      "SKU_Basic": 10.0,
      "SKU_Premium": 20.0,
      "SKU_ShortLife": 15.0
    }
  },
  "constraints": {
    "moq": 0,
    "pack_size": 1,
    "budget_per_period": null,
    "waste_limit_pct": null
  },
  "network": {
    "sub_edges": [
      [
        "SKU_Basic",
        "SKU_Premium"
      ]
    ],
    "trans_edges": [
      [
        "DC1",
        "DC2"
      ],
      [
        "DC1",
        "DC3"
      ],
      [
        "DC1",
        "DC4"
      ],
      [
        "DC1",
        "DC5"
      ],
      [
        "DC2",
        "DC1"
      ],
      [
        "DC2",
        "DC3"
      ],
      [
        "DC2",
        "DC4"
      ],
      [
        "DC2",
        "DC5"
      ],
      [
        "DC3",
        "DC1"
      ],
      [
        "DC3",
        "DC2"
      ],
      [
        "DC3",
        "DC4"
      ],
      [
        "DC3",
        "DC5"
      ],
      [
        "DC4",
        "DC1"
      ],
      [
        "DC4",
        "DC2"
      ],
      [
        "DC4",
        "DC3"
      ],
      [
        "DC4",
        "DC5"
      ],
      [
        "DC5",
        "DC1"
      ],
      [
        "DC5",
        "DC2"
      ],
      [
        "DC5",
        "DC3"
      ],
      [
        "DC5",
        "DC4"
      ]
    ]
  }
}
```

[OUTPUT FORMAT]
- Import: import gurobipy as gp; from gurobipy import GRB; import json
- Set Gurobi params: m.Params.OutputFlag = 0; m.Params.Threads = 1; m.Params.Seed = 0
- Print at end:
  print(f"status: {{m.Status}}")
  if m.Status == 2:
      print(f"objective: {{m.ObjVal}}")
- Output ONLY executable Python code. No markdown, no explanations.

[TASK]
Write a GurobiPy script that:
1. Parses the JSON data above (use json.loads on the string)
2. Models and solves the optimization problem
3. Prints status and objective value

Standard seasonal retail scenario.