This is not fixed. The accepted fix doesn't take NotImplemented into account, with the result that comparing two mutually-incomparable objects whose ordering operations were generated with total_ordering causes a stack overflow instead of the expected "TypeError: unorderable types: Foo() op Bar()". I've attached a fix for this. It properly takes NotImplemented into account. It also generates __eq__ from __ne__ and vice versa if only one of them exists.