Update bandit_trainer.py
Update bandit_trainer.py

pylint
ufal/neuralmonkey,ufal/neuralmonkey,juliakreutzer/bandit-neuralmonkey,juliakreutzer/bandit-neuralmonkey,juliakreutzer/bandit-neuralmonkey,juliakreutzer/bandit-neuralmonkey,ufal/neuralmonkey,ufal/neuralmonkey,juliakreutzer/bandit-neuralmonkey,ufal/neuralmonkey