Fixed error loading dataset without weights
Fixed error loading dataset without weights

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