example_item_data_dict.json

{
    "1":{
        "item_number":1,
        "mass":10,
        "delivery_time":1
    },
    "2":{
        "item_number":2,
        "mass":20,
        "delivery_time":2
    },
    "3":{
        "item_number":3,
        "mass":30,
        "delivery_time":3
    }
}