/**
  * @param      $namespace string
  * @param      $group     string
  * @param      $key       string
  *
  * @param null $locale
  * @param bool $useLottery
  * @param bool $findOrNew
  *
  * @return \Vsch\TranslationManager\Models\Translation|null
  */
 public function missingKey($namespace, $group, $key, $locale = null, $useLottery = false, $findOrNew = false)
 {
     $group = $namespace && $namespace !== '*' ? $namespace . '::' . $group : $group;
     if (!in_array($group, $this->config()['exclude_groups']) && $this->config()['log_missing_keys']) {
         $lottery = 1;
         if ($useLottery && $this->config()['missing_keys_lottery'] !== 1) {
             $lottery = Session::get($this->config()['persistent_prefix'] . 'lottery', '');
             if ($lottery === '') {
                 $lottery = rand(1, $this->config()['missing_keys_lottery']);
                 Session::put($this->config()['persistent_prefix'] . 'lottery', $lottery);
             }
         }
         if ($lottery === 1) {
             $locale = $locale ?: $this->app['config']['app.locale'];
             if ($findOrNew) {
                 $translation = Translation::firstOrNew(array('locale' => $locale, 'group' => $group, 'key' => $key));
             } else {
                 $translation = Translation::firstOrCreate(array('locale' => $locale, 'group' => $group, 'key' => $key));
             }
             return $translation;
         }
     }
     return null;
 }