code: func (smtj *SageMakerTrainingJob) MarshalJSON() ([]byte, error) {
  	return smtj.BaseTask.marshalMergedParams("arn:aws:states:::sagemaker:createTrainingJob.sync",
  		&smtj.parameters)
  }
docs: // MarshalJSON for custom marshalling, since this will be stringified and we need it
  // to turn into a stringified
  // Ref: https://docs.aws.amazon.com/step-functions/latest/dg/connectors-sqs.html