public function find(IDataObject $object)
 {
     $key = self::getObjectName($object);
     if (array_key_exists($key, $this->mapRegistry)) {
         $doc = new DataObjectCollection($object);
         $doc->setMapper($this);
         return $doc;
     } else {
         throw new \Exception("Can't find Map for " . get_class($object));
     }
 }