Remove unnecessary use of enumerate
Remove unnecessary use of enumerate

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