impl/python.py

Imports name this capability’s declared dependencies, which fune builds next to it in your project; each one links to its page.

from .money_amount import Money, money  ← from money.amount ^1.0.0 · built alongside by fune
from .property_deposit_cap import RentPeriod  ← from property.deposit-cap ^1.0.0 · built alongside by fune

# Keeps annual rent exact as a JavaScript number; the same limit here.
_MAX_MINOR = 1_000_000_000_000


def holding_deposit_cap(rent: Money, rent_period: RentPeriod) -> Money:
    """One week's rent, the statutory maximum holding deposit: the annual rent
    divided by 52, rounded down once so the deposit can never exceed the cap."""
    if rent.currency != "GBP":
        raise ValueError("rent must be in GBP, received %s" % (rent.currency,))
    if rent.minor < 0:
        raise ValueError("rent must not be negative, received %r" % (rent.minor,))
    if rent_period == "weekly":
        annual = rent.minor * 52
    elif rent_period == "monthly":
        annual = rent.minor * 12
    elif rent_period == "annual":
        annual = rent.minor
    else:
        raise ValueError('unknown rent period "%s"' % (rent_period,))
    if annual > _MAX_MINOR:
        raise ValueError("annual rent must be at most %d minor units" % (_MAX_MINOR,))
    return money(annual // 52, "GBP")