code: public function getSetting($setting)
      {
          $settings = $this->getSettings();
          if (isset($settings) && count($settings) > 0) {
              if (isset($settings[$setting])) {
                  return $settings[$setting];
              }
          }
  
          return '';
      }
docs: Return just one custom setting or empty string if it does
  not exist.
  
  @param string $setting
  
  @return string