Generate a list of :class:`~sagemaker.local_session.Volume` required for the container to start.

        It takes a folder with the necessary files for training and creates a list of opt volumes that
        the Container needs to start.

        Args:
            host (str): container for which the volumes will be generated.
            subdirs (list): list of subdirectories that will be mapped. For example: ['input', 'output', 'model']

        Returns: (list) List of :class:`~sagemaker.local_session.Volume`

def _build_optml_volumes(self, host, subdirs):
        """Generate a list of :class:`~sagemaker.local_session.Volume` required for the container to start.

        It takes a folder with the necessary files for training and creates a list of opt volumes that
        the Container needs to start.

        Args:
            host (str): container for which the volumes will be generated.
            subdirs (list): list of subdirectories that will be mapped. For example: ['input', 'output', 'model']

        Returns: (list) List of :class:`~sagemaker.local_session.Volume`
        """
        volumes = []

        for subdir in subdirs:
            host_dir = os.path.join(self.container_root, host, subdir)
            container_dir = '/opt/ml/{}'.format(subdir)
            volume = _Volume(host_dir, container_dir)
            volumes.append(volume)

        return volumes