Parse ISO-8601 datetime string.

    Args:
        __string: Datetime string to parse
    Returns:
        Parsed datetime object

def parse_datetime(__string: str) -> datetime.datetime:
    """Parse ISO-8601 datetime string.

    Args:
        __string: Datetime string to parse
    Returns:
        Parsed datetime object
    """
    if not __string:
        datetime_ = datetime.datetime.now(datetime.timezone.utc)
    else:
        # pylint: disable=no-member
        datetime_ = ciso8601.parse_datetime(__string)
    if datetime_.tzinfo is None:
        datetime_ = datetime_.replace(tzinfo=datetime.timezone.utc)
    return datetime_