def from_corpus(
        cls,
        *,
        corpus_id: str,
        include_metadata: bool = False,
        metadata_keys: Optional[List[str]] = None,
    ) -> "GoogleVectorStore":
        """
        Create an instance that points to an existing corpus.

        Args:
            corpus_id (str): ID of an existing corpus on Google's server.
            include_metadata (bool, optional): Specifies whether to include custom metadata in the
                query results. Defaults to False, meaning metadata will not be included.
            metadata_keys (Optional[List[str]], optional): Specifies which metadata keys to include
                in the query results if include_metadata is set to True. If None, all metadata keys
                are included. Defaults to None.

        Returns:
            An instance of the vector store that points to the specified corpus.

        Raises:
            NoSuchCorpusException if no such corpus is found.

        """
        try:
            import llama_index.vector_stores.google.genai_extension as genaix
        except ImportError:
            raise ImportError(_import_err_msg)

        _logger.debug(f"\n\nGoogleVectorStore.from_corpus(corpus_id={corpus_id})")
        client = genaix.build_semantic_retriever()
        if genaix.get_corpus(corpus_id=corpus_id, client=client) is None:
            raise NoSuchCorpusException(corpus_id=corpus_id)

        return cls(
            corpus_id=corpus_id,
            client=client,
            include_metadata=include_metadata,
            metadata_keys=metadata_keys,
        )

        Create an instance that points to an existing corpus.

        Args:
            corpus_id (str): ID of an existing corpus on Google's server.
            include_metadata (bool, optional): Specifies whether to include custom metadata in the
                query results. Defaults to False, meaning metadata will not be included.
            metadata_keys (Optional[List[str]], optional): Specifies which metadata keys to include
                in the query results if include_metadata is set to True. If None, all metadata keys
                are included. Defaults to None.

        Returns:
            An instance of the vector store that points to the specified corpus.

        Raises:
            NoSuchCorpusException if no such corpus is found.

        
llama-index-integrations/vector_stores/llama-index-vector-stores-google/llama_index/vector_stores/google/base.py