Refactor helper methods
Refactor helper methods

hvy/chainer,chainer/chainer,jnishi/chainer,sinhrks/chainer,delta2323/chainer,tkerola/chainer,kikusu/chainer,wkentaro/chainer,keisuke-umezawa/chainer,ktnyt/chainer,niboshi/chainer,hvy/chainer,cupy/cupy,truongdq/chainer,niboshi/chainer,kikusu/chainer,okuta/chainer,cupy/cupy,ronekko/chainer,rezoo/chainer,cupy/cupy,keisuke-umezawa/chainer,keisuke-umezawa/chainer,niboshi/chainer,chainer/chainer,truongdq/chainer,t-abe/chainer,hvy/chainer,ktnyt/chainer,AlpacaDB/chainer,keisuke-umezawa/chainer,niboshi/chainer,jnishi/chainer,pfnet/chainer,jnishi/chainer,wkentaro/chainer,benob/chainer,muupan/chainer,sinhrks/chainer,benob/chainer,chainer/chainer,jnishi/chainer,cemoody/chainer,aonotas/chainer,muupan/chainer,ktnyt/chainer,okuta/chainer,hvy/chainer,t-abe/chainer,cupy/cupy,wkentaro/chainer,ktnyt/chainer,AlpacaDB/chainer,ysekky/chainer,anaruse/chainer,chainer/chainer,okuta/chainer,kiyukuta/chainer,kashif/chainer,okuta/chainer,wkentaro/chainer