/**
  *	Activate the GoogleLogger
  *	
  *	@param $code mixed:
  *		String the Google Analytics code to be used in the JS snippet or
  *		String 'SiteConfig' for using the SiteConfig to configure this value or
  *		Null if you hardcode the JS snippet into your template. The JS snippet will not be included through Requirements
  *
  **/
 public static function activate($code = null)
 {
     switch ($code) {
         case null:
             self::$google_analytics_code = null;
             break;
         case 'SiteConfig':
             SiteConfig::add_extension('GoogleConfig');
             break;
         default:
             self::$google_analytics_code = $code;
     }
     Controller::add_extension('GoogleLogger');
     if (substr(GoogleAnalyzer::get_sapphire_version(), 0, 3) == '2.3') {
         Director::add_callback(array("GoogleLogger", "onAfterInit23"));
     }
 }