Unify check_forward and unify check_backward
Unify check_forward and unify check_backward

benob/chainer,okuta/chainer,benob/chainer,yanweifu/chainer,wkentaro/chainer,kikusu/chainer,masia02/chainer,hvy/chainer,keisuke-umezawa/chainer,muupan/chainer,ysekky/chainer,kiyukuta/chainer,cupy/cupy,ktnyt/chainer,ikasumi/chainer,truongdq/chainer,sinhrks/chainer,Kaisuke5/chainer,niboshi/chainer,chainer/chainer,muupan/chainer,sou81821/chainer,anaruse/chainer,ytoyama/yans_chainer_hackathon,t-abe/chainer,pfnet/chainer,keisuke-umezawa/chainer,jnishi/chainer,niboshi/chainer,cupy/cupy,t-abe/chainer,ktnyt/chainer,tscohen/chainer,hvy/chainer,ronekko/chainer,cupy/cupy,niboshi/chainer,kikusu/chainer,cemoody/chainer,keisuke-umezawa/chainer,hvy/chainer,wavelets/chainer,wkentaro/chainer,AlpacaDB/chainer,tkerola/chainer,okuta/chainer,woodshop/complex-chainer,jnishi/chainer,keisuke-umezawa/chainer,sinhrks/chainer,umitanuki/chainer,truongdq/chainer,hidenori-t/chainer,wkentaro/chainer,kashif/chainer,minhpqn/chainer,chainer/chainer,chainer/chainer,aonotas/chainer,hvy/chainer,cupy/cupy,woodshop/chainer,laysakura/chainer,jnishi/chainer,ktnyt/chainer,rezoo/chainer,kuwa32/chainer,AlpacaDB/chainer,niboshi/chainer,jnishi/chainer,chainer/chainer,ktnyt/chainer,delta2323/chainer,wkentaro/chainer,1986ks/chainer,okuta/chainer,okuta/chainer,tigerneil/chainer