def get_lookups_config(cls, mode: str) -> Tuple[List[str], List[str]]:
        """Returns the lookups configuration settings for a given mode for use
        in Lemmatizer.load_lookups.

        mode (str): The lemmatizer mode.
        RETURNS (Tuple[List[str], List[str]]): The required and optional
            lookup tables for this mode.
        """
        if mode == "lookup":
            return (["lemma_lookup"], [])
        elif mode == "rule":
            return (["lemma_rules"], ["lemma_exc", "lemma_index"])
        return ([], [])
Returns the lookups configuration settings for a given mode for use
        in Lemmatizer.load_lookups.

        mode (str): The lemmatizer mode.
        RETURNS (Tuple[List[str], List[str]]): The required and optional
            lookup tables for this mode.
        
spacy/pipeline/lemmatizer.py