Pretty prints how much time is left to a deadline

remaining_time.py

#!/usr/bin/python3
import sys
from datetime import datetime, timedelta, timezone


def get_remaining_time(total_seconds: int) -> str:
    months, remainder = divmod(total_seconds, 2592000)
    days, remainder = divmod(remainder, 86400)
    hours, remainder = divmod(remainder, 3600)
    minutes, seconds = divmod(remainder, 60)
    ret = ''
    if months > 0.0:
        ret += f'{int(months)} months, '
    if days > 0.0:
        ret += f'{int(days)} days, '
    if hours > 0.0:
        ret += f'{int(hours)} hours, '
    if minutes > 0.0:
        ret += f'{int(minutes)} minutes, '
    ret += f'{int(seconds)} seconds.'
    return ret


if __name__ == "__main__":
    if len(sys.argv) != 2:
        sys.exit('Missing date in ISO 8601. E.g., "2015-10-21T23:59-1200"')
    deadline = datetime.strptime(sys.argv[1], '%Y-%m-%dT%H:%M%z')
    utc_now = datetime.now(timezone.utc)
    now = utc_now.astimezone()
    if deadline < now:
        print('OUT OF TIME!!!')
    else:
        remaining_time = deadline - now
        print(get_remaining_time(remaining_time.total_seconds()))