private function registerCustomHandlers()
    {
        API::error(function (UnauthorizedHttpException $e) {
            return $this->handleUnauthorized($e);
        });
        API::error(function (AuthorizationException $e) {
            return $this->handleAuthorizationError($e);
        });
        Api::error(function (PermissionsException $e) {
            return $this->handleAuthorizationError($e);
        });
        API::error(function (ValidationException $e) {
            return $this->handleValidation($e);
        });
        API::error(function (ModelNotFoundException $e) {
            return $this->handleModelNotFound($e);
        });
    }