docs: def _get_entity_id_if_container_metric(self, labels):
          """
          Checks the labels indicate a container metric,
          then extract the container id from them.
  
          :param labels
          :return str or None
          """
          if CadvisorPrometheusScraperMixin._is_container_metric(labels):
              pod = self._get_pod_by_metric_label(labels)
              if is_static_pending_pod(pod):
                  # If the pod is static, ContainerStatus is unavailable.
                  # Return the pod UID so that we can collect metrics from it later on.
                  return self._get_pod_uid(labels)
              return self._get_container_id(labels)