def test_not_to_fails(self):
     self.foo = 4
     with self.assertRaises(ExpectationError):
         with expect.not_to(change, lambda: self.foo):
             self.foo = 6
 def test_not_to_passes(self):
     self.foo = 4
     with expect.not_to(change, lambda: self.foo):
         pass