code: def extend(cls, name):
          
          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,), {})
docs: 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