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

def _execute(self, ifile, process):
        """ 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

        """
        self._record_writer.write_records(process(self._records(ifile)))
        self.finish()