Return a list of field names matching a prop key/val

        :param prop_key: key name
        :param prop_val: value
        :return: list

def get_fields_by_prop(cls, prop_key, prop_val):
        """ Return a list of field names matching a prop key/val

        :param prop_key: key name
        :param prop_val: value
        :return: list
        """

        ret = []

        for key, val in cls.get_fields_with_prop(prop_key):
            if val == prop_val:
                ret.append(key)
        return ret