* New attr.cmp_using helper function
* Updated cmp_using to use new_class instead of direct patching
* Removed stray annotation that make tests fail in PY2
* Skip test if PY2 because it won't raise TypeError when a method returns NotImplemented
* Skip test if PY2 because it won't raise TypeError when a method returns NotImplemented
* Fixed PY2 tests related to total_ordering
* Added tests to complete converage
* Moved class_name argument to definition and made it non-optional
* Fixed typo in variable name
* Revert accidental black formatting of __init__.pyi in commit 2b7970bf
Co-authored-by: Hynek Schlawack <hs@ox.cx>
71b4638b32