def file_dump(self, data, filename):  # pylint: disable=no-self-use
        """
        Dump the data to a JSON formatted file
        :param data: data to be dumped
        :param filename: name of the file to use. Only the file name, not the full path!
        :return: dumped file absolute file name
        """
        dump = json.dumps(data, indent=4,
                          separators=(',', ': '), sort_keys=True)
        path = os.path.join(self.folder or os.getcwd(), filename)
        try:
            dfile = open(path, "wt")
            dfile.write(dump)
            dfile.close()
            return path
        except (OSError, IndexError) as exp:  # pragma: no cover, should never happen
            logger.exception("Error when writing the list dump file %s : %s", path, str(exp))
        return None
Dump the data to a JSON formatted file
        :param data: data to be dumped
        :param filename: name of the file to use. Only the file name, not the full path!
        :return: dumped file absolute file name