public function batchDestroy(Variable $variable, Request $request)
 {
     if ($request->has('value_ids')) {
         $valueIds = $request->get('value_ids');
         $idsArr = json_decode($valueIds);
         DataValue::destroy($idsArr);
         Cache::flush();
         return redirect()->route('variables.show', $variable->id)->with('message', 'Values deleted.')->with('message-class', 'success');
     }
     return redirect()->route('variables.show', $variable->id);
 }