code: def assert_is_not(self, actual_val, unexpected_type,
                        failure_message='Expected type not to be "{1}," but was "{0}"'):
          
          assertion = lambda: unexpected_type is not actual_val
          self.webdriver_assert(assertion, unicode(failure_message).format(actual_val, unexpected_type))
docs: Calls smart_assert, but creates its own assertion closure using
          the expected and provided values with the 'is not' operator