code: func (m *kubeGenericRuntimeManager) getKubeletSandboxes(all bool) ([]*runtimeapi.PodSandbox, error) {
  	var filter *runtimeapi.PodSandboxFilter
  	if !all {
  		readyState := runtimeapi.PodSandboxState_SANDBOX_READY
  		filter = &runtimeapi.PodSandboxFilter{
  			State: &runtimeapi.PodSandboxStateValue{
  				State: readyState,
  			},
  		}
  	}
  
  	resp, err := m.runtimeService.ListPodSandbox(filter)
  	if err != nil {
  		klog.Errorf("ListPodSandbox failed: %v", err)
  		return nil, err
  	}
  
  	return resp, nil
  }
docs: // getKubeletSandboxes lists all (or just the running) sandboxes managed by kubelet.