def _get_collection_mapping(self, collection: str) -> MutableMappingT:
        """Get a collection mapping. Create one if it does not exist."""
        if collection not in self._collections_mappings:
            self._collections_mappings[collection] = self._mapping_factory()
        return self._collections_mappings[collection]
Get a collection mapping. Create one if it does not exist.
llama-index-core/llama_index/core/storage/kvstore/types.py