Add type hint
Add type hint

niboshi/chainer,niboshi/chainer,niboshi/chainer,chainer/chainer,hvy/chainer,wkentaro/chainer,wkentaro/chainer,hvy/chainer,chainer/chainer,hvy/chainer,wkentaro/chainer,chainer/chainer,chainer/chainer,hvy/chainer,pfnet/chainer,niboshi/chainer,wkentaro/chainer