 extension View.DataController: UICollectionViewDataSource, UICollectionViewDelegate {
 
     func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
-        return 3
+        if let view = view, let dataSource = view.dataSource {
+            return dataSource.shelfView(view, numberOfItemsInSection: collectionView.tag)
+        }
+        return 1
     }
 
     func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

        }

        return cell
    }

}

        }
        cell.collectionView.delegate = self
        cell.collectionView.dataSource = self
        cell.collectionView.tag = indexPath.row // TODO: replace tag to other variable

        return cell
    }
