public function getWikiBatches($wikiId, $langCode, $numberOfBatches)
 {
     wfProfileIn(__METHOD__);
     $visualization = new CityVisualization();
     $batches = $visualization->getWikiBatches($wikiId, $langCode, $numberOfBatches);
     $out = array();
     if (!empty($batches)) {
         $out = $this->prepareBatchesForVisualization($batches);
     }
     wfProfileOut(__METHOD__);
     return $out;
 }