public function addDealerFolder(ChildDealerFolder $l)
    {
        if ($this->collDealerFolders === null) {
            $this->initDealerFolders();
            $this->collDealerFoldersPartial = true;
        }

        if (!in_array($l, $this->collDealerFolders->getArrayCopy(), true)) { // only add it if the **same** object is not already associated
            $this->doAddDealerFolder($l);
        }

        return $this;
    }