def METHOD_NAME(db):
    """Method to test monthly invoices"""
    TicketFeesFactory(service_fee=10.23, maximum_fee=11, country='global')
    test_order = OrderSubFactory(
        status='completed',
        event__state='published',
        completed_at=monthdelta(this_month_date(), -1),
        amount=100,
    )
    role, _ = get_or_create(Role, name='owner', title_name='Owner')
    UsersEventsRoles(user=UserFactory(), event=test_order.event, role=role)
    AttendeeSubFactory(event=test_order.event, order=test_order)
    db.session.commit()
    send_monthly_event_invoice()
    event_invoice = test_order.event.invoices[0]
    assert event_invoice.amount == 10.23