surfshop.py

from datetime import datetime
from typing import Optional

MAX_SURFBOARDS = 4


class TooManyBoardsError(Exception):
    # pass
    def __str__(self) -> str:
        return f'Cart cannot have more than {MAX_SURFBOARDS} surfboards in it!'


class CheckoutDateError(Exception):
    # pass
    def __str__(self) -> str:
        return 'Checkout date must be in the future.'


class ShoppingCart:
    def __init__(self) -> None:
        self.num_surfboards: int = 0
        self.checkout_date: Optional[datetime] = None
        self.locals_discount: bool = False

    def add_surfboards(self, quantity: int=1) -> str:
        if self.num_surfboards + quantity > MAX_SURFBOARDS:
            raise TooManyBoardsError()
        self.num_surfboards += quantity
        suffix = '' if quantity == 1 else 's'
        return f'Successfully added {quantity} surfboard{suffix} to cart!'

    def set_checkout_date(self, date: datetime) -> None:
        if date <= datetime.now():
            raise CheckoutDateError()
        self.checkout_date = date

    def apply_locals_discount(self):
        # pass # gives failure as doesn't set locals discount to true
        self.locals_discount = True