Well, I was filling my new tank a couple days ago, and much to my chagrin my shiny new python wouldn't fit my Price Pfister faucet. Apparently Price Pfister uses a non-standard outside thread on their faucets, which is slightly smaller than the brass fitting Python includes with their product. I ended up using the garden hose from the basement laundry tub to fill the tank, but I wanted a solution for future water changes.
Python recommends their "universal adapter":
You may have received a 69HD brass adapter instead of the 13A. For faucets with inside threads use as provided. For faucets with outside threads, remove the large white washer. Attach adapter to faucet and attach top of faucet putmp to adapter. In the rare circumstance that it does not fit, you may need a universal adapter. One may be ordered through our Replacement Parts page.
I wanted to have a little cleaner solution since I didn't really want to tighten a hose clamp every time I needed to do aquarium maintenance.
After some web searching I found this at Ace Hardware:
"Ace Faucet Adapter (A036128B)"
That part number is not valid in the stores though, you want the 43802 part, which is the exact same thing.
I'm happy to report that it fits perfectly. I'll be leaving it permanently attached to the python, so I can use it as intended.
Just thought I'd share in case anyone else faces this problem...