code: func (ds *dockerService) GetPodPortMappings(podSandboxID string) ([]*hostport.PortMapping, error) {
  	// TODO: get portmappings from docker labels for backward compatibility
  	checkpoint := NewPodSandboxCheckpoint("", "", &CheckpointData{})
  	err := ds.checkpointManager.GetCheckpoint(podSandboxID, checkpoint)
  	// Return empty portMappings if checkpoint is not found
  	if err != nil {
  		if err == errors.ErrCheckpointNotFound {
  			return nil, nil
  		}
  		errRem := ds.checkpointManager.RemoveCheckpoint(podSandboxID)
  		if errRem != nil {
  			klog.Errorf("Failed to delete corrupt checkpoint for sandbox %q: %v", podSandboxID, errRem)
  		}
  		return nil, err
  	}
  	_, _, _, checkpointedPortMappings, _ := checkpoint.GetData()
  	portMappings := make([]*hostport.PortMapping, 0, len(checkpointedPortMappings))
  	for _, pm := range checkpointedPortMappings {
  		proto := toAPIProtocol(*pm.Protocol)
  		portMappings = append(portMappings, &hostport.PortMapping{
  			HostPort:      *pm.HostPort,
  			ContainerPort: *pm.ContainerPort,
  			Protocol:      proto,
  			HostIP:        pm.HostIP,
  		})
  	}
  	return portMappings, nil
  }
docs: // GetPodPortMappings returns the port mappings of the given podSandbox ID.