Travis CI: Discover undefined names in Python code (#306)

* Travis CI: Discover undefined names in Python code

Blocked by #304 and #305

* Add linter directive # noqa: F821

* Flake8: Add E722 do not use bare 'except'

* Flake8: Remove bare 'except' and open #309

#309

.travis.yml

+os: linux
+dist: focal
 language: python
-sudo: required
-dist: trusty
 services:
   - docker
-os:
-  - linux
 env:
   - JOB=check_style
+install: pip install flake8
 script:
+  - flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
   - docker run -it -v $PWD:/work -w /work paddlepaddle/paddle:latest-dev ./.teamcity/build.sh ${JOB}
 notifications:
   email:

benchmark/torch/AlphaZero/submission_template.py

@@ -538,7 +538,7 @@ game = Connect4Game()
 
 # AlphaZero players
 agent = SimpleAgent(game)
-buffer = io.BytesIO(decoded)
+buffer = io.BytesIO(decoded)  # noqa: F821 'decoded' added in gen_submission.py
 agent.load_checkpoint(buffer)
 mcts_args = dotdict({'numMCTSSims': 800, 'cpuct': 1.0})
 mcts = MCTS(game, agent, mcts_args)