Embedded Python script to validate product price and quantity metadata against posting amount

product-prices-and-quantities.ledger

python
    def price_and_quantity(price, quantity, amount):
        if not quantity:
            quantity = 1
        if not price:
            price = amount / quantity
        return amount == price * quantity

account Market
    assert price_and_quantity(tag('Price'), tag('Units'), amount)

2024-10-06 Buying drinks
    Market      $12.00    ; Product: Water
                          ; Price:: $1.00
                          ; Units:: 12
    Card:Credit $12.00