[examples] e231 fixes

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
[examples] fix e241 where it makes sense

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
Merge pull request #3714 from thisch/pep8fix_e231_e241

[examples] fix pep8 error classes e231 and e241