def extend(cls, name):
        """
        派生一个新的 leancloud.Object 子类

        :param name: 子类名称
        :type name: string_types
        :return: 派生的子类
        :rtype: ObjectMeta
        """
        if six.PY2 and isinstance(name, six.text_type):
            # In python2, class name must be a python2 str.
            name = name.encode('utf-8')
        return type(name, (cls,), {})