old_contents: from .ada_delta import AdaDelta
  from .ada_grad import AdaGrad
  from .adam import Adam
  from .momentum_sgd import MomentumSGD
  from .rmsprop import RMSprop
  from .sgd import SGD
  
new_contents: from chainer.optimizers import ada_delta
  from chainer.optimizers import ada_grad
  from chainer.optimizers import adam
  from chainer.optimizers import momentum_sgd
  from chainer.optimizers import rmsprop
  from chainer.optimizers import sgd
  
  AdaDelta = ada_delta.AdaDelta
  AdaGrad = ada_grad.AdaGrad
  Adam = adam.Adam
  MomentumSGD = momentum_sgd.MomentumSGD
  RMSprop = rmsprop.RMSprop
  SGD = sgd.SGD
  
subject: Fix optimizers/__init__.py