nanops pep8 fixes

Very minor pep8 fixes for ``nanops``.  This brings ``nanops`` into pep8 compliance.
I can do a separate code cleanup in another pull request, but for triaging purposes I think it would be best to restrict this pull request to only stylistic (non-functional) changes.  Ideally changes like you suggested should not have an affect, but they still alter the code to some degree so I think they should be kept separate.