Flarum\Core\Post::setModel PHP Method

    public static function setModel($type, $model)
    {
        static::$models[$type] = $model;
    }

 public function registerPostTypes()
 {
     $models = ['Flarum\\Core\\Post\\CommentPost', 'Flarum\\Core\\Post\\DiscussionRenamedPost'];
     $this->app->make('events')->fire(new ConfigurePostTypes($models));
     foreach ($models as $model) {
         Post::setModel($model::$type, $model);
     }
 }