I don't know about snakes, but when I moved into my apartment, the landlord asked me what pets I had, as there was a (no dog) 2 cat limit, I said I had 2 cats, three goldfish, and 2 ferrets. They initially said no to the ferrets because they said that 'rodents' were destructive and chewed on walls / wires. I had to spend the next 30 min describing that ferrets are mustelids not rodents and that they lived in a cage, not free-roaming. Finally they signed a paper stating the pets I had, and that they were all OK'd by property management. It may just take finding someone that is willing to at least listen. If you have a cage that has a locking lid, you could show them pictures of the locked tank and say that you only have one set of keys, they can't escape, and any other relevant facts about your pets that you can. I wish you luck.
