Wheezing could also be caused by loose shed in the nostrils which happens sometimes during a shed cycle. I personally don't think wheezing/whistling alone is enough to diagnose a snake with an RI. I would definitely keep a close eye on the snake. Make sure you have a hot spot of 90*-92* and your ambient temperatures are in the low 80's. If you notice any other symptoms, drooling, open mouth breathing, face rubbing etc. Then make a vet appointment.