How to using code create purchase order

Purchase Order using X++
In this post we will learn the below using X++ :
 1) How to Create Purchase Order
 2) How to Create Purchase Order Line
 3) How to Post Purchase Order

static void THK_createPurchaseOrder(Args _args)
{
    PurchTable      purchTable;
    PurchLine       pline;
    NumberSeq       ns;
    PurchID         pid;
    PurchFormLetter pl;
;
    //Create Purchase Order
    ns                      = NumberSeq::newGetNumFromCode(SalesParameters::numRefSalesId().NumberSequence);
    purchTable.initValue();
    pid                     = ns.num();
    purchTable.PurchId      = pid;
    purchTable.OrderAccount = "4202";
    purchTable.initFromVendTable();
    purchTable.insert();

    //Create Purchase Line
    pline.clear();
    pline.PurchId   = pid;
    pline.ItemId    = "1109";
    pline.createLine(NoYes::Yes,NoYes::Yes,NoYes::Yes,NoYes::Yes,NoYes::Yes,NoYes::Yes);
    info("Purchase Order Created Sucessfully");

    //Post the PO
    pl = PurchFormLetter::construct(DocumentStatus::Invoice);
    pl.update(PurchTable::find(pid), pid, SystemDateGet(),PurchUpdate::All,AccountOrder::None,false,true);
    info("Posted Sucessfully");
}