code: def master(cls, 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
docs: Show the details of the master of the cluster with id/label `cluster_id_label`.