If you are able to shut the door to the bathroom and snake-proof the rest of it, the snake might come out at night on its own. Try turning off the lights and check hourly all night long. My snake got into a speaker and I just put the speaker into a large tote and then waiting until nighttime and checked at intervals. It was around midnight that the snake came out of the speaker and I was able to grab her before she went back in.
Another thing to try is buy some bags of ice and pack them around the toilet. The snake might get uncomfortable and come out. I got my snake out of a decorative fountain by this method. I would not keep the ice there too long, the snake could get sick, but I think if you made it really cold for a couple of hours at most, it might convince the snake that it's not such a great hiding place. (and leave the lights off to make it safe for the snake to come out during this cooling process.