What if I have no fish?No, it’s not. The sand bed, when undisturbed, is home to anaerobic bacteria that will die when exposed to oxygen from the tank. When they die, there is an ammonia build-up that will kill the fish.
Even with a python, there is no way to prevent this. So you either disturb the sand bed regularly to prevent the accumulation of those anaerobic bacteria, or you leave it be and don’t disturb it.
If you decide to clean the sand bed after more than maybe 6-8 weeks of being left alone, then you need to do it slowly, one section at a time, over many weeks.