Fix docstring
Fix docstring

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