How to print Performa Sales Invoice?

static void Test_SalesFormLetter(Args _args)
{
    SalesFormLetter letter=SalesFormLetter::construct(DocumentStatus::Invoice);
    SalesTable sale = SalesTable::find('ORDR00000229');
;
    ttsBegin;
    letter.update(sale, systemDateGet(), SalesUpdate::PickingList, AccountOrder::None, true, true);
    ttsCommit;
}