code: def _get_part_reader(self, headers: 'CIMultiDictProxy[str]') -> Any:
          
          ctype = headers.get(CONTENT_TYPE, '')
          mimetype = parse_mimetype(ctype)
  
          if mimetype.type == 'multipart':
              if self.multipart_reader_cls is None:
                  return type(self)(headers, self._content)
              return self.multipart_reader_cls(
                  headers, self._content, _newline=self._newline
              )
          else:
              return self.part_reader_cls(
                  self._boundary, headers, self._content, _newline=self._newline
              )
docs: Dispatches the response by the `Content-Type` header, returning
          suitable reader instance.
  
          :param dict headers: Response headers