code: def parse_datetime(__string: str) -> datetime.datetime:
      
      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_
docs: Parse ISO-8601 datetime string.
  
      Args:
          __string: Datetime string to parse
      Returns:
          Parsed datetime object