Python caller gives no output

One tip might be to capture some of the Python processing into your FME transaction log https://support.safe.com/s/article/logging-with-python-scripts

In a PythonCaller (or PythonCreator) transformer, messages are added to the logfile with the FMELogFile object, which is part of the fmeobjects. You need to create a logger object: logger = fmeobjects.FMELogFile() and then you will need to send messages to the logger: logger.logMessageString("Hello I am Logging Now")

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As @jkr_wrk mentioned, you’re missing

self.pyoutput(feature)

The purpose of this line is to output the resulting features. At a guess, you’d want this to be on line 25, indented to the same level as line 18.

Having it here will output every feature you input into the pythoncaller

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I'm no python expert, but these lines look very strange:

y = 'true' if not feature.getattribute('Score 6 t/m 18') else 'false' 

if "bebouwing" in x and y == "true": 
I'm pretty certain this will not do what you want it to do.