importerror:failed to import Pydot. You are must install Pydot and Graphviz for ' pydotprint ' to work.

When I used the Keras visualization model, I met the above error with the following error message:

Traceback (most recent call last):
  File "HARRISON_feature_model.py", line 55, in <module>
    plot_model(model, to_file='vgg_feature_model.png', show_shapes=True, show_layer_names=False)  
  File "/home/idc/anaconda3/envs/hashtag/lib/python2.7/site-packages/keras/utils/vis_utils.py", line 131, in plot_model
    dot = model_to_dot(model, show_shapes, show_layer_names, rankdir)
  File "/home/idc/anaconda3/envs/hashtag/lib/python2.7/site-packages/keras/utils/vis_utils.py", line 52, in model_to_dot
    _check_pydot()
  File "/home/idc/anaconda3/envs/hashtag/lib/python2.7/site-packages/keras/utils/vis_utils.py", line 27, in _check_pydot
    raise ImportError('Failed to import pydot. You must install pydot'
ImportError: Failed to import pydot. You must install pydot and graphviz for `pydotprint` to work.

The solution is:

Pip install pydot-ng
pip install Graphviz

And then it's solved, my system for Ubuntu 16.04

Or:

sudo pip3 install pydot
sudo pip3 install graphviz sudo apt-get install Graphviz

The solution below is also Ubuntu 16.04, but it's Python3.

 Reference Documents

[1]. Keras implement LENET-5 Network and visualize network structure diagram. http://blog.csdn.net/qqadssp/article/details/70431236 

[2].keras Model Visualization and resolution ' Failed to Import Pydot ' problem. http://www.zhimengzhe.com/linux/353667.html