code: func applyPodPresetsOnPod(pod *api.Pod, podPresets []*settingsv1alpha1.PodPreset) {
  	if len(podPresets) == 0 {
  		return
  	}
  
  	volumes, _ := mergeVolumes(pod.Spec.Volumes, podPresets)
  	pod.Spec.Volumes = volumes
  
  	for i, ctr := range pod.Spec.Containers {
  		applyPodPresetsOnContainer(&ctr, podPresets)
  		pod.Spec.Containers[i] = ctr
  	}
  	for i, iCtr := range pod.Spec.InitContainers {
  		applyPodPresetsOnContainer(&iCtr, podPresets)
  		pod.Spec.InitContainers[i] = iCtr
  	}
  
  	// add annotation
  	if pod.ObjectMeta.Annotations == nil {
  		pod.ObjectMeta.Annotations = map[string]string{}
  	}
  
  	for _, pp := range podPresets {
  		pod.ObjectMeta.Annotations[fmt.Sprintf("%s/podpreset-%s", annotationPrefix, pp.GetName())] = pp.GetResourceVersion()
  	}
  }
docs: // applyPodPresetsOnPod updates the PodSpec with merged information from all the
  // applicable PodPresets. It ignores the errors of merge functions because merge
  // errors have already been checked in safeToApplyPodPresetsOnPod function.