FUTURE: Fixed 'if None in [...]'
FUTURE: Fixed 'if None in [...]'

... because of FutureWarning being raised, by converting to explicit
  object comparisons to None. Ok for these two instances in hess.py, since
  there are only two comparisons, but for larger numbers of comparisons
  something more elegant will be warranted.

bskinn/opan,bskinn/opan