Besides quarintine, snakes of different species generally don't interact well with each other. In your case, the ball python would be outgrown by a common boa (boa constrictor?) in a matter of weeks. Over a period of maybe 1-2 months you "could" put them together, but the boa would very quickly outgrow youy python and most likely would make it a snack.
Generally it's just not a good idea to put two species in the same cage.
Hope that helps
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Current Collection:
0.1 Antherystic elaphe guttata guttata - Corn Snake
1.0 Elaphe vulpina gloydi - Eastern Fox Snake
0.1 Elaphe obsoleta obsoleta - Black Rat Snake
0.1 Leucistic elaphe obsoleta linheimeri - Texas Ratsnake
1.1 Morelia spilota cheyni - Jungle Carpet Python
0.1 Tiliqua scincoides intermedia - Northern Blue Tongue Skink