Most certainly talk to the highest-up person you can. Get them to put something in writing on the lease AS WELL as another paper just for the agreement that will go into your file. This is important!

Do Not just try and 'hide' the snake, since a snake that big is almost impossible to hide. And you could get into tons of trouble.

If they seem stubborn, ask about a pet deposit. When we first moved into this apartment complex, a pet friendly place, the manager had no problem at all with reptiles and didn't even charge the deposit since they weren't threats to the apartment (if I'd had an Iguana, it might have changed). Things went great...until we had to renew the lease. A new manager had taken over and she HATES snakes. The office ladies, sadly, let slip that I had multiple snakes and the manager was terrified. She couldn't make me get rid of them, since the apartments allow all sorts of pets, but she DID make us pay the $300 pet deposit normally reserved for free-roaming animals only.

The point of this is, if your place gets new management and the manager isn't as 'understanding' as the current one might be and you only have a verbal agreement, things could get ugly. Any arrangements made should always be in writing, preferably in more than one source!