def METHOD_NAME(self, in_args, args=[], defaults={}, varargs=None,
            kwonlyargs=[], kwargs=None):
    argspec = self._parse(in_args)
    assert_equal(argspec.positional, args)
    assert_equal(argspec.defaults, defaults)
    assert_equal(argspec.var_positional, varargs)
    assert_equal(argspec.named_only, kwonlyargs)
    assert_equal(argspec.var_named, kwargs)