Programmable filter not recognising inputs[0]

I am having trouble creating a programmable filter, it appears that Paraview is not recognising inputs[0]. It gives an error message:
‘NoneType’ object has no attribute ‘getItem
This happens even if my filter just says something trivial like a=inputs[0]
I am using version 5.4.1.

Heather, welcome to the ParaView community. That is a mysterious error. When you created the Programmable Filter, did you have an object selected in the pipeline browser? Another thought: are you sure you created a Programmable Filter and not a Programmable Source by chance?

Yes, definitely have an object selected, and I’m definitely creating a Programmable Filter. Its very strange, I’ve not had this trouble previously.

Please provide your programmable filter code if possible.

ProgrammableFilterIntFlux.py (584 Bytes)

Hmm, nothing jumps out at me. Do you have a small example dataset that should work with this filter that you can share?