Documentation fix for issue #613
Documentation fix for issue #613

rbharath/deepchem,rbharath/deepchem,ktaneishi/deepchem,ktaneishi/deepchem,lilleswing/deepchem,Agent007/deepchem,Agent007/deepchem,ktaneishi/deepchem,peastman/deepchem,lilleswing/deepchem,miaecle/deepchem,miaecle/deepchem,Agent007/deepchem,deepchem/deepchem,lilleswing/deepchem,peastman/deepchem,miaecle/deepchem,deepchem/deepchem