Trying to convert the code below for the 2022 R1 release.  The PX.Objects.CT.CTBillEngine.ARContractInvoiceEntry graph has been removed, but I cannot find what it should be replaced with.

The code is updating some custom fields on the Invoice generated from the Run Contract Billing action.

    public delegate void BillDelegate(Nullable<Int32> contractID, Nullable<DateTime> date);
    ;PXOverride]
    public void Bill(Nullable<Int32> contractID, Nullable<DateTime> date, BillDelegate baseMethod)
    {
        PXGraph.InstanceCreated.AddHandler<PX.Objects.CT.CTBillEngine.ARContractInvoiceEntry>((graph) =>          
        {
            graph.RowInserted.AddHandler<ARInvoice>((sender, e) =>
            {
                ARInvoice inv = (ARInvoice)e.Row;
                
                 // pull value from custom UsrCustPO field
                 Contract ContractRow = Contract.PK.Find(Base, contractID);

                 // extension name:  ContractExt
                 ContractExt ext = ContractRow.GetExtension<ContractExt>();