minor fix

README.md

@@ -46,9 +46,9 @@ Tianshou(天授) is a reinforcement learning platform. The following image illus
 
 Please follow [google python coding style](https://google.github.io/styleguide/pyguide.html)
 
-Files should all be named with lower case letters and underline.
+All files/folders should be named with lower case letters and underline (except specified names such as `AlphaGo`).
 
-Try to use full names. Don't use too many abbrevations for class/function/variable names except common abbrevations (such as `num` for number, `dim` for dimension, `env` for environment, `op` for operation). For now we use `pi` to refer to the policy in examples/ppo_example.py.
+Try to use full names. Don't use abbrevations for class/function/variable names except common abbrevations (such as `num` for number, `dim` for dimension, `env` for environment, `op` for operation). For now we use `pi` to refer to the policy in examples/ppo_example.py.
 
 The """xxx""" comment should be written right after class/function. Also comment the part that's not intuitive during the code. We must comment, but for now we don't need to polish them.
 

examples/ppo_example.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
-import tensorflow as tf, numpy as np
+import tensorflow as tf
+import numpy as np
 import time
 import gym