fix for flake8
fix for flake8

wkentaro/chainer,ysekky/chainer,ktnyt/chainer,cupy/cupy,tkerola/chainer,keisuke-umezawa/chainer,jnishi/chainer,ktnyt/chainer,chainer/chainer,jnishi/chainer,rezoo/chainer,wkentaro/chainer,hvy/chainer,niboshi/chainer,wkentaro/chainer,niboshi/chainer,hvy/chainer,pfnet/chainer,kiyukuta/chainer,jnishi/chainer,ktnyt/chainer,cupy/cupy,chainer/chainer,okuta/chainer,ktnyt/chainer,keisuke-umezawa/chainer,niboshi/chainer,chainer/chainer,okuta/chainer,okuta/chainer,niboshi/chainer,jnishi/chainer,kashif/chainer,aonotas/chainer,cupy/cupy,cupy/cupy,chainer/chainer,anaruse/chainer,ronekko/chainer,wkentaro/chainer,keisuke-umezawa/chainer,hvy/chainer,okuta/chainer,keisuke-umezawa/chainer,hvy/chainer,delta2323/chainer