would it be ok to house 2 BP in the same enclosure like a 55 gallon or 2 sepret enclosures like 2 20 gallon tanks

This question will yield you a variety of answers, from a variety of different people. It also really does depend on what you mean by OK.
I'm going to assume you mean ideal, because chances are if you've taken the time to find this site and ask these questions your a responsible enough pet owner (or at least doing your best) And know the difference between whats ok, and whats ideal for an animal. While you may get away with housing two ball pythons in one 55 gallon tank, i would advise against it. there are many risks you run doing this. Reptiles don't really enjoy the company of other reptiles, and while you may never see any aggression between the two, there are many other factors that would play into the wellbeing of these animals. Stress being a big one. As for the two 20 gallon tanks, they would work for younger, juveinille snakes, a 20 long is not enough space for a adult ball python. Im not positive what the minimum suggested space is, but offhand i'd suggest getting two 40 gallon breeder tanks. Ill let those with more experience with ball pythons chime in here though.

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I personally would advise againt it. I don't believe that they will fight each other but they will compete for basking space often one laying on top of the other thus soaking up all the heat.

The suggested space for a single adult is minimum 40 gal.
I personally have my 7 year old pair living together in a 55 gal. They have been together since they a were both hatchlings. I remove them and feed them seperately out of the tank.
A lot of it will depend on the snakes. some get along and some don't. And the signs of stress are quite subtle. For a new keeper I would suggest keeping them seperately. This makes it simpler to maintain. If one has a bowel movement or regurgitation you don't find yourself trying to quess which one it was.

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Merlin,
What's Life Without A Little Magic!

if your really interested in getting two ball pythons, id check this site out, Herpers toolbox
Theres a nice stacking style of enclosures relativly easy to build.

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"Nobody can do Everything, but Everybody can do Something."