Script to tell me how much I can spend untill the next payday

money.py

#!/usr/bin/python3

import sys
import datetime


def get_money():
    try:
        return int(sys.argv[1])
    except (ValueError, IndexError):
        print("Usage: {0} <money>".format(sys.argv[0]))
        sys.exit(1)


def next_payday(today):
    try:
        return datetime.date(today.year, today.month+1, 15)
    except ValueError:
        return datetime.date(today.year+1, 1, 15)


def days_until_payday():
    today = datetime.date.today()
    if today.day == 15 and today.isoweekday() not in (6, 7):
        print("It's payday today!")
        sys.exit(0)

    return (next_payday(today) - today).days


if __name__ == "__main__":
    days = days_until_payday()
    money_per_day = get_money() / days
    print("It's {0} days until payday".format(days))
    print("You can spend {0} crowns per day".format(money_per_day))