def lookup_lemmatize(self, token: Token) -> List[str]:
        """Lemmatize using a lookup-based approach.

        token (Token): The token to lemmatize.
        RETURNS (list): The available lemmas for the string.

        DOCS: https://spacy.io/api/lemmatizer#lookup_lemmatize
        """
        lookup_table = self.lookups.get_table("lemma_lookup", {})
        result = lookup_table.get(token.text, token.text)
        if isinstance(result, str):
            result = [result]
        return result
Lemmatize using a lookup-based approach.

        token (Token): The token to lemmatize.
        RETURNS (list): The available lemmas for the string.

        DOCS: https://spacy.io/api/lemmatizer#lookup_lemmatize
        
spacy/pipeline/lemmatizer.py