我在容器中运行DeepSpeech这个项目，按照操作提示下载了容器

nvidia-docker pull hub.baidubce.com/paddlepaddle/deep_speech_fluid:latest-gpu

运行时报错：

Traceback (most recent call last):
  File "train.py", line 9, in 
    from model_utils.model import DeepSpeech2Model
  File "/DeepSpeech/model_utils/model.py", line 23, in 
    from model_utils.network import deep_speech_v2_network
  File "/DeepSpeech/model_utils/network.py", line 62, in 
    class RNNCell(fluid.layers.RNNCell):
AttributeError: 'module' object has no attribute 'RNNCell'
Failed in training!

但是查找文档又没有找到fluid.layer.RNNCell，我想问问那个文档中才有这个api