DateType = typing.Union[
    datetime.date,
    datetime.datetime,
    datetime.time,
    float,
    None,
]

def approx(date: str, *, relative_to: DateType = None) -> float:
    """
    Get a unix timestamp from an arbitrary date string.

    If `relative_to` is None, and the given date string is missing date or time,
    now will be used. Otherwise, the missing units will be filled in from the
    date/time represented by relative_to.

    If `relative_to` is a float, it's treated as a unix timestamp.
    """

import datetime

import approxidate

approxidate.approx("10/10/2013 10:10:10.312 +0500")
approxidate.approx("10/March/2013 10:10:10.312 +0500")
approxidate.approx("10/Mar/2013 10:10:10.312 +0500")
approxidate.approx("2013 march 10 04:00:07")
approxidate.approx("2013 10 march 04:00:07")

# Parsed relative to now
approxidate.approx("00:00:07.657891")
approxidate.approx("mar 10")
approxidate.approx("10 mar 2013")
approxidate.approx("march 10 2013")

rel = datetime.datetime.now() + datetime.timedelta(hours=-1)
approxidate.approx("00:00:07.657891", relative_to=rel)

rel = datetime.date.today()
approxidate.approx("00:00:07.657891", relative_to=rel)

# Relative to a unix timestamp
approxidate.approx("mar 10", relative_to=1579733041)