/**
  * Get old input by key
  * @param string $key 
  * @return mixed
  */
 public function getOldInput($key)
 {
     $this->input = $this->request->hasOldInput() !== false ? $this->request->oldInput() : array();
     // Input that is flashed to the flash can be easily retrieved by the
     // developer, making repopulating old forms and the like much more
     // convenient, since the request's previous input is available.
     return array_get($this->input, $this->transformKey($key), null);
 }