Changed conditionals for lattice outer to be more Pythonic per comments by @paulromano
Changed conditionals for lattice outer to be more Pythonic per comments by @paulromano

mjlong/openmc,shikhar413/openmc,bhermanmit/openmc,walshjon/openmc,wbinventor/openmc,amandalund/openmc,walshjon/openmc,smharper/openmc,mit-crpg/openmc,mjlong/openmc,johnnyliu27/openmc,smharper/openmc,wbinventor/openmc,bhermanmit/openmc,shikhar413/openmc,wbinventor/openmc,paulromano/openmc,kellyrowland/openmc,walshjon/openmc,samuelshaner/openmc,samuelshaner/openmc,paulromano/openmc,johnnyliu27/openmc,kellyrowland/openmc,paulromano/openmc,liangjg/openmc,shikhar413/openmc,amandalund/openmc,smharper/openmc,liangjg/openmc,mit-crpg/openmc,liangjg/openmc,wbinventor/openmc,shikhar413/openmc,paulromano/openmc,amandalund/openmc,walshjon/openmc,mit-crpg/openmc,johnnyliu27/openmc,smharper/openmc,samuelshaner/openmc,johnnyliu27/openmc,liangjg/openmc,amandalund/openmc,samuelshaner/openmc,mit-crpg/openmc