Combine / merge lists to loop over all items

Need help
1

Hello,
I want to loop over all commited items. They are in 3 lists: added, modified and deleted.
I tried this:
image
which resulted in invalid response:

{
  "items": "[\"Test/test2.md\",\"test1.md\"],[],[]"
}

I also tried to unite the lists via “+”, kind of the same result.

Is there a shorthand notation or some other elegant way to merge the lists?

Or do I have to either create a separate loop to create that list in the Activepieces Storage Module or use some sring regexp + concatenate?
Thanks!