Fix for flake8
Fix for flake8

ktnyt/chainer,chainer/chainer,wkentaro/chainer,okuta/chainer,chainer/chainer,keisuke-umezawa/chainer,hvy/chainer,ktnyt/chainer,chainer/chainer,jnishi/chainer,niboshi/chainer,keisuke-umezawa/chainer,jnishi/chainer,keisuke-umezawa/chainer,niboshi/chainer,ktnyt/chainer,niboshi/chainer,wkentaro/chainer,hvy/chainer,okuta/chainer,tkerola/chainer,ktnyt/chainer,jnishi/chainer,niboshi/chainer,jnishi/chainer,okuta/chainer,wkentaro/chainer,keisuke-umezawa/chainer,wkentaro/chainer,hvy/chainer,okuta/chainer,chainer/chainer,hvy/chainer,pfnet/chainer