def _field_names_(self):
        """ get list of field names defined in Swagger spec

        :return: a list of field names
        :rtype: a list of str
        """
        ret = []
        for n in six.iterkeys(self.__swagger_fields__):
            new_n = self.__swagger_rename__.get(n, None)
            ret.append(new_n) if new_n else ret.append(n)
        
        return ret
get list of field names defined in Swagger spec

        :return: a list of field names
        :rtype: a list of str