code: def _execute(self, ifile, process):
          
          self._record_writer.write_records(process(self._records(ifile)))
          self.finish()
docs: Default processing loop
  
          :param ifile: Input file object.
          :type ifile: file
  
          :param process: Bound method to call in processing loop.
          :type process: instancemethod
  
          :return: :const:`None`.
          :rtype: NoneType