Return the id of a pod
        :param labels:
        :return: str or None

def _get_pod_uid(self, labels):
        """
        Return the id of a pod
        :param labels:
        :return: str or None
        """
        namespace = CadvisorPrometheusScraperMixin._get_container_label(labels, "namespace")
        pod_name = CadvisorPrometheusScraperMixin._get_container_label(labels, "pod_name")
        return self.pod_list_utils.get_uid_by_name_tuple((namespace, pod_name))