Get the data by checking if the text is contained in one of the columns

[Salvodif]

I have a fairly small database from which I would like to return all records that contain a value (query) that is within author or title or tags even if only partially (so if I were to search for “tom” it should return “tommy, thomas, tomino”, etc).
Unfortunately, I don't understand where I'm going wrong for it to return what I expect.

This is the function (BTW during the tests I just remove the tags query)

    def search_books(self, query: str) -> List[Book]:
        """
        Cerca libri nel database in base a una query. La ricerca viene effettuata su author, title e tags.

        :param query: La stringa di ricerca.
        :return: Una lista di dizionari rappresentanti i libri che corrispondono alla query.
        """
        query = query.lower()
        BookQuery = Query()
        
        try:
            # Cerca libri dove il titolo o l'autore contiene la stringa della query (case insensitive)
            results = self.db.search(
                (BookQuery.title.test(lambda title: query in title.lower())) |
                (BookQuery.author.test(lambda author: query in author.lower()))
            )
            return results
        except Exception as e:
            print(f"Errore durante la ricerca dei libri: {e}")
            return []