protected static function delete_all_user_data(context_user $usercontext) {
        global $DB;
        $userid = $usercontext->instanceid;

        // Delete all blog posts.
        $recordset = $DB->get_recordset_select('post', 'userid = :userid AND module IN (:blog, :blogext)', [
            'userid' => $userid, 'blog' => 'blog', 'blogext' => 'blog_external']);
        foreach ($recordset as $record) {
            $entry = new blog_entry(null, $record);
            $entry->delete();   // Takes care of files and associations.
        }
        $recordset->close();

        // Delete all external blogs, and their associated tags.
        $DB->delete_records('blog_external', ['userid' => $userid]);
        core_tag_tag::delete_instances('core', 'blog_external', $usercontext->id);
    }