Discussion on: Daily Challenge #252 - Everybody hates Mondays

from datetime import datetime, timedelta


class Mondays():

    @staticmethod
    def count(birth: datetime, current_date: datetime):
        # For a more accurate deltatime in years use dateutil library with relativedelta instead, it supports leap years
        end_working = birth + timedelta(days=78 * 365)
        start_working = birth + timedelta(days=22 * 365)
        if current_date > end_working:
            current_date = birth + end_working
        first_monday = start_working + timedelta(days=(7 - start_working.weekday()) % 7)
        last_monday = current_date - timedelta(days=current_date.weekday())
        days_between_mondays = (last_monday - first_monday).days
        if days_between_mondays >= 7:
            return int(days_between_mondays / 7)
        return 1 if not current_date.weekday() or not start_working.weekday() else 0


try:
    mondays = Mondays.count(datetime(1995, 4, 3), datetime(2017, 4, 3))
    print (mondays)
except ValueError as ex:
    print (ex)

try:
    mondays = Mondays.count(datetime(1995, 4, 2), datetime(2018, 4, 2))
    print (mondays)
except ValueError as ex:
    print (ex)

try:
    mondays = Mondays.count(datetime(1700, 9, 20), datetime(1762, 9, 26))
    print (mondays)
except ValueError as ex:
    print (ex)

try:
    mondays = Mondays.count(datetime(-300, 12, 20), datetime(-258, 12, 22))
    print (mondays)
except ValueError as ex:
    print (ex)

try:
    mondays = Mondays.count(datetime(1000000, 2, 25), datetime(1000022, 12, 28))
    print (mondays)
except ValueError as ex:
    print (ex)