def from_existing(
        cls: Type["PropertyGraphIndex"],
        property_graph_store: PropertyGraphStore,
        vector_store: Optional[BasePydanticVectorStore] = None,
        # general params
        llm: Optional[LLM] = None,
        kg_extractors: Optional[List[TransformComponent]] = None,
        # vector related params
        use_async: bool = True,
        embed_model: Optional[EmbedType] = None,
        embed_kg_nodes: bool = True,
        # parent class params
        callback_manager: Optional[CallbackManager] = None,
        transformations: Optional[List[TransformComponent]] = None,
        storage_context: Optional[StorageContext] = None,
        show_progress: bool = False,
        **kwargs: Any,
    ) -> "PropertyGraphIndex":
        """Create an index from an existing property graph store (and optional vector store)."""
        return cls(
            nodes=[],  # no nodes to insert
            property_graph_store=property_graph_store,
            vector_store=vector_store,
            llm=llm,
            kg_extractors=kg_extractors,
            use_async=use_async,
            embed_model=embed_model,
            embed_kg_nodes=embed_kg_nodes,
            callback_manager=callback_manager,
            transformations=transformations,
            storage_context=storage_context,
            show_progress=show_progress,
            **kwargs,
        )
Create an index from an existing property graph store (and optional vector store).
llama-index-core/llama_index/core/indices/property_graph/base.py