A classic Python beginner's error: defining a function with a default argument
set to an empty list. As a result, every Wire created is connected to every
input in the circuit. How embarrassing.
For small circuits this bug doesn't break anything since gates ignore packets
with unrecognised keys (hence not being spotted earlier) but for larger
circuits you get dreadful network contention...
mundya
commented
8 years ago 
A classic Python beginner's error: defining a function with a default argument set to an empty list. As a result, every Wire created is connected to every input in the circuit. How embarrassing.
For small circuits this bug doesn't break anything since gates ignore packets with unrecognised keys (hence not being spotted earlier) but for larger circuits you get dreadful network contention...