code: public function settings($setting = null)
      {
          if (!is_null($setting)) {
              return isset($this->settings[$setting]) ? $this->settings[$setting] : null;
          }
  
          return $this->settings;
      }
docs: Returns settings values,
  when no setting is specified all the settings
  are returned, otherwise it returns the specified
  settings or null.
  
  @param setting $setting
  
  @return mixed