I tend to be quite conservative about this sort of thing, but I would never put any polishing agent of any kind on a blued gun. Anything that polishes is an abrasive, and use of an abrasive means that you're removing some amount of the oxide that forms the bluing (or some of the nickel finish on a nickeled gun, or some of the stainless steel on a stainless gun, etc.). I'd be particularly concerned if the bluing were already worn down to the bare metal on some part(s) of the gun.
Some people have reported being pleased with the results of applying a very mild abrasive like Flitz to spruce up an old blued gun. I personally wouldn't recommend it, but again, I tend to be quite conservative in this area. (By the way, Flitz says it's "non-abrasive," but that's only because it's a mild enough abrasive to fall below our federal government's minimum standard for labeling something an abrasive. It's still an abrasive.) If someone insists on doing using Flitz or an equivalent mild abrasive, they should go very slowly and gently and only use it
once.
Depending upon the wear characteristics of your Python, you might find that applying a
neutral wax like Renaissance Wax or Johnson's Paste Wax and buffing it to a shine will give you what you're looking for even without using a polishing agent. Museums (the Smithsonian, for instance) use Ren Wax to protect guns and other metal objects in their collections. Collectors commonly use Johnson's as well. A quick Google search will bring up plenty of information regarding their use on firearms. I have no idea whether these exact brands are available locally in Norway, but you could order either by Amazon, or you could locate an equivalent neutral wax.
By the way, congrats on the Python!