Help on built-in function isinstance in module builtins:

isinstance(obj, class_or_tuple, /)

    Return whether an object is an instance of a class or of a subclass thereof.

    A tuple, as in ``isinstance(x, (A, B, ...))``, may be given as the target to

    check against. This is equivalent to ``isinstance(x, A) or isinstance(x, B)

    or ...`` etc.

isinstance() 是用来检测一个对象(类的实例)是否属于一个类(class)或者其子类：

isinstance(7, int)

Out[1]: True

这里要注意：

isinstance(object, type)  # 当object作为一个对象的时候

Out[1]: True

isinstance(type, object)  # 当type作为一个对象的时候

Out[2]: True