As above the only PRODUCTION Pythons were chambered in .357 Magnum, and the Python Target in .38 Special. The Python Target is so marked on the barrel.
Colt did make up purely experimental Pythons in a few other calibers, but NONE were ever production guns and the only ones ever sold were the few experimental models sold in the big Colt collection auction.
There were other caliber Python made and sold, but these were ALL custom guns made up by gunsmiths, NOT Colt.
You'll usually see these in .41 Magnum.
Colt made about three .41 Magnum Pythons on request of a distributor, but Colt had second thoughts about safety and recalled them.
Colt was planning on making .22 Pythons and even had pictures on a 1980's catalog. However, they decided not to market it, and best info is that the .22 Pythons on the catalog cover were non-firing dummy guns.
Bottom line is, if you come across a Python in any caliber other then .357 or the plainly marked Python Target .38 Special it's not a Colt gun. If you buy a Colt archive letter on one of these altered Pythons they always letter as a standard production .357 model.
Some people just refuse to accept that a "super rare valuable Python" in some other caliber is a non-Colt conversion.
There was one poster who refused to accept his .41 Magnum Python wasn't a Colt factory gun, and actually believed that Colt was lying to him about having made it.