ErrorException [ Fatal Error ]: Class 'Helper_Core' not found

APPPATH/bootstrap.php [ 312 ]

307 	$params = redirect404( $params, $request );
308 
309 	return $params;
310 })
311 // Call helper function since routes are protected by permissions
312 ->defaults( Helper_Core::getDefaultRouteAdmin() ); 
313 
314 
315 // Set school admin routes 
316 Route::set('schooladmin', '<directory>(/<controller>(/<action>(/<id>)))', ['directory'  => 'schooladmin'])
317 ->filter(function($route, $params, $request){

1. {
   Fatal error: Class 'Helper_SiteNotification' not found in /var/www/html/application/i18n/en.php on line 245