Buy a female garden hose fitting at a hardware store. Buy how ever many feet of 3/4" vinyll hose you need at the hardware store. Buy a water bed drain & fill kit at a store like wall mart or meijers. Slip your existing aquarium vacuum into the vinyl tubing, attach a female hose adaptor to the other end, install the waterbed drain / fill venturi to your sink, screw the new hose to the venturi and do your water change. THis is cheaper than buying a real python drain & fill but it's tough to find vinyl tubing that is as flexable as what comes with the python. THis is how we used to do it before the python was introduced to the hobby.
Joel