def _get_file_metadata(self, filepath, version):
        """Return the desired file metadata.

        Returns None if the file does not exist.
        """
        if version is None:
            return file_models.FileMetadataModel.get_model(
                self._exploration_id, 'assets/%s' % filepath)
        else:
            return file_models.FileMetadataModel.get_version(
                self._exploration_id, 'assets/%s' % filepath, version)
dataset/ETHPy150Open oppia/oppia/core/domain/fs_domain.py/ExplorationFileSystem._get_file_metadata/original