If it can pass urate, it can poop (usually). Unless you have cause for concern, you should be fine. Remember that these snakes barely move much in their enclosure. Sitting in one area for hours to days don't encourage bowel movement because they are built not needing to go as often as a snake that is active. Think of it this way: in the wild, the poop smell is more potent and can attract predators and prevent prey from straying nearby, and not using much calories moving around, an ambush predator like ball pythons really don't need to BM unless it has to. My Dumerils boa (ambush predator) as a baby would eat once a week and poop once a month. Nature knows the poopy routine.