class Quickbooks::Model::InvoiceLineItem

def payment_item!
  self.detail_type = PAYMENT_LINE_DETAIL
  self.payment_line_detail = PaymentLineDetail.new
  yield self.payment_line_detail if block_given?
end

def sales_item!
  self.detail_type = SALES_LINE_ITEM_DETAIL
  self.sales_line_item_detail = SalesItemLineDetail.new
  yield self.sales_line_item_detail if block_given?
end

def sales_item?
  detail_type.to_s == SALES_LINE_ITEM_DETAIL
end

def sub_total_item?
  detail_type.to_s == SUB_TOTAL_LINE_DETAIL
end