Check this out.
https://docs.python.org/3/howto/descriptor.html#class-methods
You can also take a look at the source code for class and static method objects, in funcobject.c:
http://hg.python.org/cpython/file/69b416cd1727/Objects/funcobject.c
Class method object definition starts on line 694, while static method object definition starts on line 852. (I do find it kind of funny that they have items titled “method” in funcobject.c when methodobject.c also exists.)