code: func validateConfigBundle(ctx *validation.Context, bundle policy.ConfigBundle) {
  	ctx.SetFile(serviceAccountsCfg)
  	cfg, ok := bundle[serviceAccountsCfg].(*admin.ServiceAccountsPermissions)
  	if ok {
  		validateServiceAccountsCfg(ctx, cfg)
  	} else {
  		ctx.Errorf("unexpectedly wrong proto type %T", cfg)
  	}
  }
docs: // validateConfigBundle validates the structure of a config bundle fetched by
  // fetchConfigs.