public function getChoices()
 {
     $filters = sfPlopSlotPeer::retrieveAllByTemplate('GoogleMapsFilter', $this->getOption('page_id'), $this->getOption('page_culture'));
     $options_for_filter = array('' => '');
     foreach ($filters as $filter_object) {
         $options_for_filter[$filter_object->getValue()] = $filter_object->getValue();
     }
     $this->setOption('choices', $options_for_filter);
     return parent::getChoices();
 }