Don not return None in build_and_check
Don not return None in build_and_check

Raise an exception instead.

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