/**
  * @param LoggerInterface
  */
 public static function addHelpers(LoggerInterface $logger)
 {
     $self = get_called_class();
     $ref = new \ReflectionClass($self);
     $methods = $ref->getMethods(\ReflectionMethod::IS_STATIC);
     $classParts = explode('\\', $self);
     array_pop($classParts);
     $namespace = implode('\\', $classParts);
     foreach ($methods as $method) {
         $name = $method->getName();
         if (strpos($name, 'on') === 0) {
             $eventName = substr($name, 2);
             $eventClass = $namespace . '\\' . $eventName;
             $logger->addHelper($eventClass, array($self, $name));
         }
     }
 }