Anacondas, Pythons, and Pythons

With anacondas, it's quite an interesting approach because most snakes you look for in the wet season. And to be honest, it would be very foolish for an individual person to try and capture a large, reticulated python - they're easily capable of killing a human. But sometimes it's just nice to stand there and watch the animal and see what it's doing. So at the other end of the spectrum then, what's the smallest species of snake?