2 - Automatic query expansion built by the Search API.
    """
    spell_correction_mode: int = Field(default=2, ge=0, le=2)
    """Specification to determine under which conditions query expansion should occur.
    0 - Unspecified spell correction mode. In this case, server behavior defaults 
        to auto.
    1 - Suggestion only. Search API will try to find a spell suggestion if there is any
        and put in the `SearchResponse.corrected_query`.
        The spell suggestion will not be used as the search query.
    2 - Automatic spell correction built by the Search API.
        Search will be based on the corrected query if found.
    """
    _client: SearchServiceClient
    _serving_config: str
    class Config:
        """Configuration for this pydantic object."""
        extra = Extra.ignore
        arbitrary_types_allowed = True
        underscore_attrs_are_private = True
    def __init__(self, **kwargs: Any) -> None:
        """Initializes private fields."""
        try:
            from google.cloud.discoveryengine_v1beta import SearchServiceClient
        except ImportError as exc:
            raise ImportError(
                "google.cloud.discoveryengine is not installed."
                "Please install it with pip install google-cloud-discoveryengine"
            ) from exc
        super().__init__(**kwargs)
        #  For more information, refer to:
        # https://cloud.google.com/generative-ai-app-builder/docs/locations#specify_a_multi-region_for_your_data_store
        self._client = SearchServiceClient(
            credentials=self.credentials,
            client_options=self.client_options,
            client_info=get_client_info(module="vertex-ai-search"),
        )
        self._serving_config = self._client.serving_config_path(