Fixed bug in Python API Chi.get_xs(...) when summed across nuclides
Fixed bug in Python API Chi.get_xs(...) when summed across nuclides

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