Fix pylint complaints introduced in commit e58f87a9

Due to a small mistake I missed three non-critical pylint complaints for
commit e58f87a9. They're fixed with this patch.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>