Download the collection rules gpg signature

def get_collection_rules_gpg(self, collection_rules):
        """
        Download the collection rules gpg signature
        """
        sig_text = self.fetch_gpg()
        sig_response = NamedTemporaryFile(suffix=".asc")
        sig_response.write(sig_text.encode('utf-8'))
        sig_response.file.flush()
        self.validate_gpg_sig(collection_rules.name, sig_response.name)
        self.write_collection_data(self.collection_rules_file + ".asc", sig_text)