TypeError: unhashable type: ‘dict’ when upload json data

def insert_data():
    # The list of objects with their associated data.
    farmers = [
        {"W":1000000,"Z":22758,"J1_I":0.66},
        {"W":3500000,"Z":21374,"J1_I":2.69},
        {"W":2500000,"Z":14321,"J1_I":0.76},
        {"W":2500000,"Z":14321,"J1_I":0.76}
    ]
    # An object is created for each record and added to a list.
    farmer_objects = [Farmers(**data) for data in farmers]
    # The objects created are added to the session.
    db.session.add_all(farmer_objects)
    # The session is closed and the objects it contains are saved.
    db.session.commit()