code: def get_writable_metadata(self, file_format):
          
          if file_format == 'json':
              metadata = self.json
          elif file_format == 'xml':
              metadata = self.xml
          else:
              raise TypeError('The requested file type (%s) is not yet supported'
                              % file_format)
          return metadata
docs: Convert the metadata to a writable form.
  
          :param file_format: the needed format can be json or xml
          :type file_format: str
          :return: the dupled metadata
          :rtype: str