@classmethod
def _map_tuning_objective(cls, objective_type, objective_metric_name):
    """
        Construct a dictionary of tuning objective from the arguments

        Args:
            objective_type (str): The type of the objective metric for evaluating training jobs.
                This value can be either 'Minimize' or 'Maximize'.
            objective_metric_name (str): Name of the metric for evaluating training jobs.

        Returns:
            A dictionary of tuning objective. For format details, please refer to
            HyperParameterTuningJobObjective as described in
            https://botocore.readthedocs.io/en/latest/reference/services/sagemaker.html#SageMaker.Client.create_hyper_parameter_tuning_job
        """
    tuning_objective = None
    if objective_type is not None or objective_metric_name is not None:
        tuning_objective = {}
    if objective_type is not None:
        tuning_objective['Type'] = objective_type
    if objective_metric_name is not None:
        tuning_objective['MetricName'] = objective_metric_name
    return tuning_objective
