I don't know how to train for dangerous snakes because we don't have them here but imagine it's the same way to keep dogs away from skunks, my own traps and snares.
I put the dog on sit within 20 feet of a set and let him watch while I place the trap or snare, all the while intoning noooh, noooh, noooh, reinforced with hand commands for sit-stay. A dog knows when you mean business.
The next time we approach a set I act as if it's a runaway nuclear reactor, moving slightly off the trail, scowling at the dog, noohing in a low voice. Shoot a skunk or porcupine and act as if it's poison. Works---unless you have a palooka.