moodle 2

protected function render_custom_menu(custom_menu $menu) {
    global $USER;
    // If the menu has no children return an empty string
    if (!$menu->has_children()) {
        return '';
    }
    
    if (isloggedin()){             
        $useremail=$USER->email;  
        
        // acording to the email address we detect if the user is the teacher and similar to moodle 1 enable or disable the button