[fix] flake8
[fix] flake8

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