def METHOD_NAME(self):
    dead_letter_config = {"Type": "SQS", "QueueLogicalId": {"Fn::Sub": "MyDLQ${Env}"}}
    self.eb_event_source.DeadLetterConfig = dead_letter_config
    with self.assertRaises(InvalidEventException):
        self.eb_event_source.to_cloudformation(function=self.func)