LGTM Python alert fixes

[hernando]

This pull request fixes 65 alerts when merging 0f46bbe678dc752ca8fc9fc5a3a6c05c0e591b96 into 078ed7f3d16204378d1bebfd420f0f7aa097adaa - view on LGTM.com

fixed alerts:

• 24 for Unused import
• 12 for Unused local variable
• 11 for Except block handles 'BaseException'
• 7 for Testing equality to None
• 6 for 'import *' may pollute namespace
• 2 for Comparison of identical values
• 1 for Unnecessary pass
• 1 for Variable defined multiple times
• 1 for Unnecessary delete statement in function

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