removed dangerous function call

Models/DifficultyModel.php

@@ -58,7 +58,6 @@ final class DifficultyModel
     public static function deleteByID($I_id)
     {
         $O_model = Model::get();
-        UserModel::anonymiseByID($I_id);
         $stmt = $O_model->prepare("DELETE FROM DIFFICULTY WHERE ID=:id");
         $stmt->bindParam("id", $I_id);
         $stmt->execute();