old_contents: from deepmark_chainer.net import alex
  from deepmark_chainer.net import big_lstm
  from deepmark_chainer.net import c3d
  from deepmark_chainer.net import deepspeech2
  from deepmark_chainer.net import fc5
  from deepmark_chainer.net import inception_v3
  from deepmark_chainer.net import resnet_50
  from deepmark_chainer.net import small_lstm
  from deepmark_chainer.net import vgg
  
new_contents: from deepmark_chainer.net import alex
  from deepmark_chainer.net import big_lstm
  from deepmark_chainer.net import c3d
  from deepmark_chainer.net import deepspeech2
  from deepmark_chainer.net import fc5
  from deepmark_chainer.net import inception_v3
  from deepmark_chainer.net import resnet_50
  from deepmark_chainer.net import small_lstm
  from deepmark_chainer.net import vgg
  from deepmark_chainer.net import vgg_d
  
subject: Add vgg_d to net.__init__