Function QuantityDiscount(quantity)
    'For the sake of the example, just return a fixed amount
    QuantityDiscount = 10
End Function

Function ErrorXML()
   Dim sXML
   
   sXML = "<Error><Reason>Invalid numbers</Reason></Error>"
   
   ErrorXML = sXML
End Function

Function SuccessXML(sDiscount, sExtprice)
   Dim sXML
   
   sXML = "<updateTotalResponse>" & vbNewLine
   sXML = sXML & "   <discount>" & sDiscount & "</discount>" & vbNewLine
   sXML = sXML & "   <extPrice>" & sExtprice & "</extPrice>" & vbNewLine
   sXML = sXML & "</updateTotalResponse>"
   
   SuccessXML = sXML
End Function