ubuntu 16.04:Couldn't import dot_parser, loading of dot files will not be possible.

我在跑别人的模型的时候，出现了下面的错误输出：

Couldn't import dot_parser, loading of dot files will not be possible.
我的配置是 pyparsing 2.2.0，pydot 1.2.3，然后我用了下面的命令，就没有出现上述的错误了：

sudo pip install pyparsing==1.5.7
sudo pip install pydot==1.0.28

参考文献

[1].pydot and graphviz error: Couldn't import dot_parser, loading of dot files will not be possible.https://stackoverflow.com/questions/15951748/pydot-and-graphviz-error-couldnt-import-dot-parser-loading-of-dot-files-will