Output file name doesn't match GUI input

So I have an input GUI for my participants where they are just supposed to enter their ID (“Teilnehmer_ID”), which should then be added to the name of the output file.

BUT, this doesn’t seem to work. Instead, I always get “PARTICIPANT” at the beginning of all my output files.
E.g. PARTICIPANT_Tiere_in_Farbe_Home_2020-10-29_10h10.26.878.csv

The implementation should be correct in my code though (see below) - can’t make sense of it. Don’t even know where the capitalised “PARTICIPANT” comes from.

You could add print statements at different points to see where this change gets made:
One after dlg is closed, print('1', expInfo['Teilnehmer_ID'])
One after the expInfo['psychopyVersion'] =... bit, print('2', expInfo['Teilnehmer_ID'])
One after filename is defined, print('3', filename)
and then a last one before the file is saved, print('4', filename)

That way you’ll be able to see at what point is stops being the value you entered and starts being PARTICIPANT