Various stylistic fixes

- Fix PEP8's line too long warning
- Remove useless parentheses
- Use triple quotes for docstring
- Address pylint's 'inconsistent-return-statements'
- Specify string format arguments as logging function parameters
- Comment out already disabled block of code
- Remove useless else (after return)
- Remove useless statement
- Do not import already imported module

whipper/command/cd.py

@@ -191,6 +191,8 @@ class _CD(BaseCommand):
         if self.options.eject in ('success', 'always'):
             utils.eject_device(self.device)
 
+        return None
+
     def doCommand(self):
         pass