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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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)