code: func (g *KubeVersionGetter) KubeletVersions() (map[string]uint16, error) {
  	nodes, err := g.client.CoreV1().Nodes().List(metav1.ListOptions{})
  	if err != nil {
  		return nil, errors.New("couldn't list all nodes in cluster")
  	}
  	return computeKubeletVersions(nodes.Items), nil
  }
docs: // KubeletVersions gets the versions of the kubelets in the cluster