Silverstripe adding pages via model admin doesn't update CMS

I need to create a model admin class to be able to create pages in model admin style. It used to work on 2.4 but not since LeftAndMain::ForceReload has been deprecated in 3.1 it doesn't work anymore. Here is a fragment of my CustomCalendarEvent class:

public function onBeforeWrite(){
parent::onBeforeWrite();
$parent_calendar_page = Calendar::get()->first();
$this->ParentID = $parent_calendar_page->ID;
}

public function onAfterWrite(){
parent::onAfterWrite();
if(!$this->isPublished()){
$this->publish('Stage', 'Live');
$this->flushCache();
// This doesn't work anymore on SS 3.1
// LeftAndMain::ForceReload();
}
}