Gee, if I got a dollar for every time I've answered that question I'd be rich! Seems the experienced keepers are fighting against the pet shop "experts" who have vested interests in selling stuff keepers don't need.
as far as i know and my experience is, pythons don't need UVB lights because they get the calcium from the bones of they prey they eat unlike lizards that eat insects which dont have bones or if they dont eat insects they need calcium powder and UVB to get enough