swift234

[gardening] Fix violations of non-controversial PEP8 rules.

Fixes:
* blank line at end of file
* closing bracket does not match indentation of opening bracket's line
* continuation line over-indented for hanging indent
* continuation line over-indented for visual indent
* continuation line unaligned for hanging indent
* inline comment should start with '# '
* missing whitespace around arithmetic operator
* missing whitespace around bitwise or shift operator
* multiple imports on one line
* multiple spaces after ':'
* multiple spaces after operator