code: func (a *AuthCommand) TryRun(cmd string, client auth.ClientI) (match bool, err error) {
  	switch cmd {
  	case a.authGenerate.FullCommand():
  		err = a.GenerateKeys()
  	case a.authExport.FullCommand():
  		err = a.ExportAuthorities(client)
  	case a.authSign.FullCommand():
  		err = a.GenerateAndSignKeys(client)
  	case a.authRotate.FullCommand():
  		err = a.RotateCertAuthority(client)
  	default:
  		return false, nil
  	}
  	return true, trace.Wrap(err)
  }
docs: // TryRun takes the CLI command as an argument (like "auth gen") and executes it
  // or returns match=false if 'cmd' does not belong to it