Python interface: add comments and consistency checks
Python interface: add comments and consistency checks

dftlibs/xcfun,dftlibs/xcfun,robertodr/xcfun,robertodr/xcfun,dftlibs/xcfun,bast/xcfun,robertodr/xcfun,bast/xcfun,dftlibs/xcfun,bast/xcfun,robertodr/xcfun,bast/xcfun