Iron Phyton Script include null

[Wee Loon Goh]

Hi,

I'm new to Spotfire. I'm trying to create a multi input line box in text area for my user to fill in the order number that their need. But there are times when they require null value to be included also. I can only manage create a iron python script that manage to accept all the order numbers. But if there are the needs of null value to be included, the report will results in blank. Is there a way / a script to include null value

Below is the script i'm using

import re

string = Document.Properties['InputOrderNumber']

list = [x.strip() for x in string.split('n')]

Document.Properties['ListOrderNumber'] = list

Thanks in advance