Address Flake8 issues

[mssalvatore]

Flake8 currently finds the following issues:

Address all flake8 issues. This is a prerequisite for #974.

• Create a configuration for flake8. Ensure travis uses the same configuration. Adjust these tasks as necessary. (0d) - @shreyamalviya
• Edit travis config so that the build fails if black finds any flake8 errors. (0d) - @mssalvatore
• Resolve E722, W293, W605 issues (0d) - @shreyamalviya
• Resolve E402, F401, F841 issues (0d) - @shreyamalviya
• Resolve E501 issues. A good number of these will be resolved by Reformat all code with black #1070 (0d) - @VakarisZ
• Run blackbox and unit tests to ensure nothing wonky happened (0.25d) - @mssalvatore

[mssalvatore]

This might be helpful information: https://black.readthedocs.io/en/stable/compatible_configs.html#flake8