code: func validateDefaults(ctx *validation.Context, title string, d *admin.ServiceAccountRuleDefaults) {
  	ctx.Enter(title)
  	defer ctx.Exit()
  	validateScopes(ctx, "allowed_scope", d.AllowedScope)
  	validateMaxGrantValidityDuration(ctx, d.MaxGrantValidityDuration)
  }
docs: // validateDefaults checks ServiceAccountRuleDefaults proto.