对象父子关系鉴定

>>> class Student():
      def __init__(self,id,name):
        self.id = id
        self.name = name

>>> class Undergraduate(Student): 
       pass

# 判断 Undergraduate 类是否为 Student 的子类 
>>> issubclass(Undergraduate,Student)
True

#第二个参数可为元组：
>>> issubclass(int,(int,float))
True