Conditional test explicitly against None.
Conditional test explicitly against None.

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