ValueError: item id not in item id mappings while making item features

---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
in ()
----> 1 item_features=dataset.build_item_features(itemFeatures)

2 frames
/usr/local/lib/python3.6/dist-packages/lightfm/data.py in _process_features(self, datum)
90 raise ValueError(
91 "{entity_type} id {entity_id} not in {entity_type} id mappings.".format(
---> 92 entity_type=self._entity_type, entity_id=entity_id
93 )
94 )

ValueError: item id 6Qg39Zo6sZk not in item id mappings.

Start at the reported call to dataset.build_item_features(itemFeatures) and inspect _process_features in lightfm/data.py, where the traceback is raised. Reproduce the failing feature build and determine what input or mapping condition causes the item ID error; done means the reported operation completes without this ValueError.

Written by the indexing model from the issue text.