Fix flake8
Fix flake8

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