Lighting is not necessary for ball pythons.  They prefer a dark cave like enclosure.  Ambient room lighting is adequate for giving your snake a day night cycle.  If you want to add some lighting, try a low wattage bulb or a color light bulb.  The light should be on for a maximum of twelve hours.  If you want night lighting, to see your snake when it is most active, use a light bulb designed for night viewing.  Ball pythons do not require uvb like may other reptiles.