docs: def parse_str(mmp_bytes, content_type, encoding='utf-8'):
      """Parse multipart document bytes into a tuple of BodyPart objects.
  
      Args:
        mmp_bytes: bytes
          Multipart document.
  
        content_type : str
          Must be on the form, ``multipart/form-data; boundary=<BOUNDARY>``, where
          ``<BOUNDARY>`` is the string that separates the parts of the multipart document
          in ``mmp_bytes``. In HTTP requests and responses, it is passed in the
          Content-Type header.
  
        encoding : str
          The coding used for the text in the HTML body.
  
      Returns:
        tuple of BodyPart
          Members: headers (CaseInsensitiveDict), content (bytes), text (Unicode),
          encoding (str).
  
      """
      return requests_toolbelt.multipart.decoder.MultipartDecoder(
          mmp_bytes, content_type, encoding
      ).parts