remove type annotation for _Constant.fill_value
remove type annotation for _Constant.fill_value

okuta/chainer,tkerola/chainer,wkentaro/chainer,hvy/chainer,hvy/chainer,niboshi/chainer,okuta/chainer,chainer/chainer,okuta/chainer,keisuke-umezawa/chainer,chainer/chainer,wkentaro/chainer,keisuke-umezawa/chainer,keisuke-umezawa/chainer,chainer/chainer,niboshi/chainer,hvy/chainer,niboshi/chainer,niboshi/chainer,wkentaro/chainer,keisuke-umezawa/chainer,chainer/chainer,wkentaro/chainer,pfnet/chainer,hvy/chainer,okuta/chainer