old_contents: # For backward compatibility
  from  chainer.training.triggers.interval_trigger import IntervalTrigger
  from chainer.training.util import get_trigger
  from chainer.training.util import _never_fire_trigger
  
new_contents: # For backward compatibility
  from chainer.training.triggers.interval_trigger import IntervalTrigger  # NOQA
  from chainer.training.util import _never_fire_trigger  # NOQA
  from chainer.training.util import get_trigger  # NOQA
  
subject: Fix flake8