Fix flake8 issues
Fix flake8 issues
pfnet/chainer,niboshi/chainer,wkentaro/chainer,chainer/chainer,hvy/chainer,ktnyt/chainer,wkentaro/chainer,hvy/chainer,jnishi/chainer,anaruse/chainer,jnishi/chainer,ktnyt/chainer,keisuke-umezawa/chainer,ktnyt/chainer,ktnyt/chainer,rezoo/chainer,keisuke-umezawa/chainer,niboshi/chainer,ronekko/chainer,keisuke-umezawa/chainer,keisuke-umezawa/chainer,niboshi/chainer,niboshi/chainer,hvy/chainer,chainer/chainer,wkentaro/chainer,hvy/chainer,chainer/chainer,okuta/chainer,okuta/chainer,okuta/chainer,okuta/chainer,tkerola/chainer,jnishi/chainer,jnishi/chainer,chainer/chainer,wkentaro/chainer