builder with or without db saving and relational objects

builder.py

# with relational objects and with sawing to database

(
    ChargeBuilder(database)
    .with_customer(CustomerBuilder(database).build())
    .with_delivery_date(DeliveryDateBuilder(database).build())
    .build()
)

# simple builder
customer = CustomerBuilder().build()
database.save_customer(customer)

delivery_date = DeliveryDateBuilder().build()
database.save_delivery_date(delivery_date)

charge = (
    ChargeBuilder()
    .with_delivery_date(delivery_date)
    .with_customer(customer)
)
database.save_charge(charge)