>>>from typingimport Sized>>>isinstance(1, Sized)False

>>>from typingimport Sized, Protocol>>>classFoo(Sized,Protocol):pass...>>>isinstance(1, Sized)Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "C:\Users\alexw\coding\cpython\Lib\typing.py", line 1153, in __instancecheck__    return self.__subclasscheck__(type(obj))           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  File "C:\Users\alexw\coding\cpython\Lib\typing.py", line 1428, in __subclasscheck__    return issubclass(cls, self.__origin__)           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  File "<frozen abc>", line 123, in __subclasscheck__  File "C:\Users\alexw\coding\cpython\Lib\typing.py", line 1793, in __subclasscheck__    return super().__subclasscheck__(other)           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  File "<frozen abc>", line 123, in __subclasscheck__  File "C:\Users\alexw\coding\cpython\Lib\typing.py", line 1876, in _proto_hook    raise TypeError("Instance and class checks can only be used with"TypeError: Instance and class checks can only be used with @runtime_checkable protocols

>>>import typing>>>isinstance(1, typing.Sized)False>>>classFoo(typing.Sized,typing.Protocol):pass...>>>isinstance(1, typing.Sized)False