public function add($data)
 {
     $placement_qty = new Model_PlacementQuantity();
     $placement_qty->ccm_id = $data['coldchain'];
     $placement_qty->quantity = $data['quantity'];
     $placement_qty->stock_batch_warehouse_id = $data['batchID'];
     $placement_qty->save();
     return $placement_qty->getLast();
 }