def zero_datetime(dt, tz=None):
    """
    Return the given datetime with hour/minutes/seconds/ms zeroed and the
    timezone coerced to the given ``tz`` (or UTC if none is given).
    """
    if tz is None:
        tz = get_current_timezone()
    return coerce_naive(dt).replace(hour=0, minute=0, second=0, microsecond=0)
Return the given datetime with hour/minutes/seconds/ms zeroed and the
    timezone coerced to the given ``tz`` (or UTC if none is given).