Creating folders of menu items in the wagtail admin

wagtail_hooks.py

class CoursesAdminMenu(Menu):
    """
    A Courses-specific submenu in the wagtail admin sidebar 
    """

    def __init__(self):
        super().__init__(register_hook_name='register_courses_admin_menu_item')


class CoursesAdminSubmenu(SubmenuMenuItem):

    def __init__(self):
        super().__init__(
            'Courses',
            CoursesAdminMenu(),
            classnames='icon icon-fa-institution',
            order=115
        )

    def is_shown(self, request):
        """
        Hide this menu unless we have a CoursIndexPge the current user has permission to use it.
        """
        user_has_perms = request.user.is_admin_or_editor(site)
        course_listing_exists = CourseIndexPage2.objects.in_site(site).exists()
        return user_has_perms and course_listing_exists


@hooks.register('register_admin_menu_item')
def register_admin_courses_menu():
    return CoursesAdminSubmenu()


class CourseManagementDashboardMenuItem(MenuItem):

    def __init__(self):
        # Rather than specifying these in the constructor, we let the class hard-code them for itself.
        super().__init__(
            label='Course Management Dashboard',
            url=reverse('caltech_sites_admin:course_management_dashboard'),
            classnames='icon icon-doc-full',
            order=102
        )

    def is_shown(self, request):
        site = Site.find_for_request(request)
        return CourseIndexPage2.objects.in_site(site) and request.user.is_admin_or_editor(site)


@hooks.register('register_courses_admin_menu_item')
def register_course_management_dashboard():
    return CourseManagementDashboardMenuItem()