code: func NewCmdCompletion(out io.Writer, boilerPlate string) *cobra.Command {
  	cmd := &cobra.Command{
  		Use:     "completion SHELL",
  		Short:   "Output shell completion code for the specified shell (bash or zsh)",
  		Long:    completionLong,
  		Example: completionExample,
  		Run: func(cmd *cobra.Command, args []string) {
  			err := RunCompletion(out, boilerPlate, cmd, args)
  			kubeadmutil.CheckErr(err)
  		},
  		ValidArgs: GetSupportedShells(),
  	}
  
  	return cmd
  }
docs: // NewCmdCompletion returns the "kubeadm completion" command