Custom trigger does not executes python code

Hi, I am quite new in Dataiku and I am interested why the following code does not work as expected. Namely, I am trying to define custom trigger that will check if the folder is empty.
Both

from dataiku.scenario import Trigger

t=Trigger()
folder = dataiku.Folder("folder_id")
files = folder.list_paths_in_partition()

if files:
  t.fire()

and

from dataiku.scenario import Trigger


t=Trigger()

client = dataiku.api_client()
project = client.get_default_project()
folder = project.get_managed_folder("project_id")
files = f.list_contents()["items"]

if files:
  t.fire()

do not fire the trigger. I cannot open the logs since I do not have appropriate permissions I guess.

Do you have any suggestions how to solve this?

Thank you!