def _embedding_source_column(self) -> dict:
        """
        Return the embedding source column configs as a dictionary.
        Empty if the index is not a Databricks-managed embedding index.
        """
        return next(
            iter(self._delta_sync_index_spec.get("embedding_source_columns") or []),
            {},
        )

        Return the embedding source column configs as a dictionary.
        Empty if the index is not a Databricks-managed embedding index.
        
llama-index-integrations/vector_stores/llama-index-vector-stores-databricks/llama_index/vector_stores/databricks/base.py