def fetch(self, is_dl_forced=False):
        """
        We fetch GeneReviews id-label map and id-omim mapping files from NCBI.
        :return: None
        """
        self.get_files(is_dl_forced)

        # load and tag a list of OMIM IDs with types
        self.omim_type = self.find_omim_type()

        return