def _group_metadata(self, metadata, track_mbid_map):
        results = {}
        for track_id, mbids in track_mbid_map.iteritems():
            mbids = set(mbids)
            results[track_id] = []
            for item in metadata:
                if mbids in item['recording_id']:
                    results[track_id].append(item)
        return results.iteritems()
dataset/ETHPy150Open lalinsky/acoustid-server/acoustid/api/v2/__init__.py/LookupHandler._group_metadata/swapped operands of `in`