fix bug, empty function should return nothing (#225)
fix bug, empty function should return nothing (#225)


robertnishihara/ray,amplab/ray,Wapaul1/ray,Wapaul1/ray,atumanov/ray,ray-project/ray,atumanov/ray,stephanie-wang/ray,amplab/ray,alanamarzoev/ray,richardliaw/ray,ray-project/ray,pcmoritz/ray-1,ray-project/ray,ray-project/ray,robertnishihara/ray,pcmoritz/ray-1,robertnishihara/ray,richardliaw/ray,pcmoritz/ray-1,alanamarzoev/ray,robertnishihara/ray,atumanov/ray,atumanov/ray,robertnishihara/ray,amplab/ray,pcmoritz/ray-1,atumanov/ray,alanamarzoev/ray,richardliaw/ray,stephanie-wang/ray,robertnishihara/ray,robertnishihara/ray,atumanov/ray,pcmoritz/ray-1,stephanie-wang/ray,stephanie-wang/ray,richardliaw/ray,ujvl/ray-ng,Wapaul1/ray,atumanov/ray,alanamarzoev/ray,alanamarzoev/ray,ujvl/ray-ng,Wapaul1/ray,richardliaw/ray,stephanie-wang/ray,Wapaul1/ray,amplab/ray,pcmoritz/ray-1,pcmoritz/ray-1,pcmoritz/ray-1,stephanie-wang/ray,richardliaw/ray,richardliaw/ray,alanamarzoev/ray,robertnishihara/ray,robertnishihara/ray,stephanie-wang/ray,ujvl/ray-ng,ray-project/ray,ujvl/ray-ng,ray-project/ray,atumanov/ray,richardliaw/ray,Wapaul1/ray,ray-project/ray,stephanie-wang/ray,stephanie-wang/ray,ray-project/ray