You may find it easier to use a the Find list operation on your list to look for a matching object. This will return either one matching object or empty if there is no match.
https://docs.mendix.com/refguide/list-operation/#member-inspections
I hope this helps. Good luck!
Hi Tiago,
As Robert already mentioned, you can use the 'List operation' activity to Find a specific instance in a list. In the example below, it tries to find an instance of RequiredDocument in the retrieved list that has DocumentId '123456'. If there is a document with that ID in the list, it will return it. If not, it will return empty.
Hi Taigo,
Retrieve your list -> use list operation activity -> inside list operation select find -> select any member (you want to find on the basis of that member) -> inside equals section pass your $currentObject/member_Name(if you want dynamically) otherwise give static value.