Hacky wrapper for dateparser.parse() that handles christmas and new year

fudge_datetime.py

import datetime
import re

import dateparser

def fudge_datetime(s: str, now: datetime.datetime = None) -> datetime.datetime:
    """
    Return a best guess datetime for the free-form string s, relative to now.

    >>> fudge_datetime("Christmas Day 2020")
    datetime.datetime(2020, 12, 25, 23, 59, 59)
    >>> fudge_datetime("yesterday", now=datetime.datetime(2020, 2, 28, 12, 00)
    datetime.datetime(2020, 2, 27, 23, 59, 59)

    Assumptions:
    - the date/time in `s` occurs before the date/time `now`
    """
    # TODO Timezones
    wip = s

    # Replace references to holidays with dates
    # TODO Easter
    holidays = {
        "christmas eve": "24 December",
        "christmas day": "25 December",
        "boxing day": "26 December",
        "new year's eve": "31 December",
        "new years eve": "31 December",
        "new year's day": "1 January",
        "new years day": "1 January",
    }
    holiday_patt = re.compile(
        # NB Relies on Python 3.6+ stable dict ordering
        r'|'.join(re.escape(holiday) for holiday in holidays),
        flags=re.IGNORECASE,
    )
    def holiday_repl(m: re.Match) -> str:
        holiday = m.group(0).lower()
        return holidays[holiday]
    wip = holiday_patt.sub(holiday_repl, wip)

    last_patt = re.compile(r'^last\s+', flags=re.IGNORECASE)
    wip = last_patt.sub('', wip)
    dt = dateparser.parse(wip)

    if dt is None:
        raise ValueError(repr(s))

    # Initialise this *after* parsing, so the sanity check passes for s=='today'
    if now is None:
        now = datetime.datetime.now()

    if dt > now:
        raise ValueError(f'{s=!r} {dt=} {now=}')

    # If s contained time information, use it
    if dt.time() > datetime.time(0):
        return dt

    return dt.replace(hour=23, minute=59, second=59)