protected function registerPresenceVerifierProvider()
    {
        if ($this->isLumen()) {
            $this->app->singleton('validator', function () {
                $this->app->register(PresenceVerifierProvider::class);

                return $this->app->make('validator');
            });
        } else {
            $this->app->register(PresenceVerifierProvider::class);
        }
    }