Cobra子命令默认调用帮助

Question

I want sub command to print out the Help menu if no argument or flags is passed (The main command does this by default).

For example, the main command without any arguments or flags:

chris@pop-os:~$ ./tk
Command line application to deploy

Usage:
  tk [command]

Available Commands:
  addon       Install packages
  cluster     Used to create cloud infrastructures
  help        Help about any command

Flags:
      --config string   config file (default is $HOME/.tk8.yaml)
  -h, --help            help for tk
  -t, --toggle          Help message for toggle

Use "tk [command] --help" for more information about a command.

I want subcommand like "tk addon" to also return it's own help menu if no arguments or flags is entered, currently it only gives a blank line.

addon code :

var addonCmd = &cobra.Command{
    Use:   "addon",
Short: "Install addon packages",
Long: `Install additional packages`,
Run: func(cmd *cobra.Command, args []string) {

        }
    },
}