Use ValueError instead of RuntimeError.
Use ValueError instead of RuntimeError.

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