def test_get_async_param(self):
        """
        L{twisted.python.compat._get_async_param} uses isAsync by default,
        or deprecated async keyword argument if isAsync is None.
        """
        self.assertEqual(_get_async_param(isAsync=False), False)
        self.assertEqual(_get_async_param(isAsync=True), True)
        self.assertEqual(
            _get_async_param(isAsync=None, **{'async': False}), False)
        self.assertEqual(
            _get_async_param(isAsync=None, **{'async': True}), True)
        self.assertRaises(TypeError, _get_async_param, False, {'async': False})

        L{twisted.python.compat._get_async_param} uses isAsync by default,
        or deprecated async keyword argument if isAsync is None.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_compat.py