[AIRFLOW-3789] Fix flake8 3.7 errors.

[jmcarp]

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Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-3789
  • In case you are fixing a typo in the documentation you can prepend your commit with [AIRFLOW-XXX], code changes always need a Jira issue.

Description

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Tests

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Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

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  • When adding new operators/hooks/sensors, the autoclass documentation generation needs to be added.
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Code Quality

• Passes flake8

[XD-DENG]

Hi @jmcarp , thanks for picking up this Flake8 issue quickly.

May you fix the errors caused by this line?

[codecov-io]

Codecov Report

Merging #4617 into master will increase coverage by <.01%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master    #4617      +/-   ##
==========================================
+ Coverage   74.25%   74.26%   +<.01%     
==========================================
  Files         423      423              
  Lines       27779    27782       +3     
==========================================
+ Hits        20628    20631       +3     
  Misses       7151     7151

Impacted Files	Coverage Δ
airflow/contrib/operators/winrm_operator.py	0% <0%> (ø)	⬆️
airflow/config_templates/airflow_local_settings.py	72.72% <0%> (ø)	⬆️
airflow/contrib/operators/mlengine_operator.py	76.57% <100%> (ø)	⬆️
airflow/contrib/kubernetes/pod_launcher.py	90.16% <100%> (+0.08%)	⬆️
.../kubernetes_request_factory/pod_request_factory.py	100% <100%> (ø)	⬆️
airflow/contrib/operators/ssh_operator.py	83.75% <100%> (ø)	⬆️
airflow/contrib/hooks/gcp_dataflow_hook.py	75.75% <100%> (ø)	⬆️
airflow/contrib/utils/gcp_field_validator.py	91.52% <100%> (+0.07%)	⬆️
airflow/contrib/hooks/imap_hook.py	95.41% <33.33%> (ø)	⬆️

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[jmcarp]

Sorry @ashb, I didn't see your comment and force-pushed over your commit.

[ashb]

No probs - it's quite odd that as a commiter of this repo I can push commits to your PR branch :D. I merged your one though.