D365 How to convert Unit of measure

public PurchQty convertPurchQtyToSalesUnit_DEV(PurchQty _purchQty,ItemId _itemId,PurchUnit _purchUnit,SalesUnit _salesUnit )
{
PurchQty purchQty;
purchQty = UnitOfMeasureConverter::convert(_purchQty,
UnitOfMeasure::unitOfMeasureIdBySymbol(_purchUnit),
UnitOfMeasure::unitOfMeasureIdBySymbol(_salesUnit),
NoYes::Yes,
InventTable::itemProduct(_itemId),
NoYes::Yes);
return purchQty;
}