WARNING: Undefined variable $group_modifiers at line 192 in /var/www/search_engine/seek_quarry/src/controllers/GroupController.php
  in seekquarry\yioop\controllers\GroupController->processSession, line 113 in /var/www/search_engine/seek_quarry/src/controllers/GroupController.php 
  called from seekquarry\yioop\controllers\GroupController->processRequest, line 200 in /var/www/search_engine/seek_quarry/src/index.php 
  called from seekquarry\yioop\bootstrap, line 59 in /var/www/search_engine/seek_quarry/index.php 
  called from seekquarry\yioop\passthruYioopRequest, line 391 in /var/www/search_engine/seek_quarry/src/library/WebSite.php 
  called from seekquarry\yioop\library\WebSite->trigger, line 350 in /var/www/search_engine/seek_quarry/src/library/WebSite.php 
...