The interrupt.py example is broken on python3.5, because of changes that were made to signal handling in python as described by PEP 0475. As explained in zeromq/pyzmq#746, pyzmq now retries calls to ...

Cannot interrupt Interactive Python cell execution, both Interrupt and Restart don't work while Keras model fitting. model.fit(X_train, y_train, validation_data=(X_test, y_test), batch_size=16, ...