'Register a callback to be executed during tearDownClass.
Parameters
callback : callable
The callback to invoke at the end of the test suite.'

@final
@classmethod
def add_class_callback(cls, callback, *args, **kwargs):

    if cls._in_setup:
        raise ValueError('Attempted    to    add    a    class    callback    in    init_instance_fixtures.\nDid    you    mean    to    call    add_instance_callback?')
    return cls._class_teardown_stack.callback(callback, *args, **kwargs)
