import datetime from dateutil import tz from pytimeparse import timeparse def timedelta_type(value): """Return the :class:`datetime.datetime.DateTime` for a time in the past. :param value: a string containing a time format supported by mod:`pytimeparse` """ if value is None: return None return datetime_seconds_ago(timeparse.timeparse(value)) def datetime_seconds_ago(seconds): now = datetime.datetime.now(tz.tzutc()) return now - datetime.timedelta(seconds=seconds)