@classmethod
def master(cls, cluster_id_label):
    """
        Show the details of the master of the cluster with id/label `cluster_id_label`.
        """
    cluster_status = cls.status(cluster_id_label)
    if cluster_status.get('state') == 'UP':
        return list(filter(lambda x: x['role'] == 'master', cluster_status.
            get('nodes')))[0]
    else:
        return cluster_status
