paymentnbilling/
    controllers/
        Advance.php
        Dashboard.php
    models/
        Paymentnbilling_model.php
    views/
        advance/
            patient_manage.php
        components/
            invoice_status.php
            patient_payment_info.php
            top-widgets.php
            transaction-details.php
        paymentnbilling/
            dashboard.php