Load external code from .txt for custom column

Good afternoon community,

I have a problem that I am trying to solve. I have a bit of code (for a custom column) that is quite critical for our reporting but which is also annoying to maintain in 6 different reports.

With the help of a blogpost (https://blog.crossjoin.co.uk/2014/02/04/loading-power-query-m-code-from-text-files/) I tried to load the code for the custom column externally, but without results. 

The point is, I am only trying to load the code for a custom code externally, not all content of the advanced editor. 

When creating the custom column I tried code like this:
Expression.Evaluate(Text.FromBinary(Web.Contents("https://xxxxx.xxxx.x.xxx/Subvlak.txt")))

Where Subvlak.txt is just a plain .txt with content like this: 

if [Modul] = "035" or ([Modul] = "022" and [#"HPG-Code"] = "003") then "Datacenter" else "Blabla"

I then get an error like this: 

Expression.Error: There is an unknown identifier. Did you use the [field] shorthand for a _[field] outside of an 'each' expression?

Anyone can help me with this? Thanks in advance!

With kind regards,

Lutijn