if the MDF was created with memory='minimum' and new
        channels have been appended, then this must be called just before the
        object is not used anymore to clean-up the temporary file

def close(self):
        """ if the MDF was created with memory='minimum' and new
        channels have been appended, then this must be called just before the
        object is not used anymore to clean-up the temporary file

        """
        if self._tempfile is not None:
            self._tempfile.close()
        if self._file is not None and not self._from_filelike:
            self._file.close()