code: public function old(string $key, $default = null, bool $trim = true, bool $clean = true)
      {
          $value = $this->request->old($key, $default);
  
          return $this->clean($value, $trim, $clean);
      }
docs: Get an old input item from the request.
  
  @param string $key
  @param mixed  $default
  @param bool   $trim
  @param bool   $clean
  
  @return mixed