Write multiline string to temp file, return filename

        data: a multiline string to be written to a file.

def _input_as_multiline_string(self, data):
        """Write multiline string to temp file, return filename

        data: a multiline string to be written to a file.
        """
        self._input_filename = self.getTmpFilename(
            self.WorkingDir, suffix='.fasta')
        with open(self._input_filename, 'w') as f:
            f.write(data)
        return self._input_filename