Addresses 
Addresses in SmartPy are of type sp.address. They are written as sp.address("tz1Ke2h7sDdakHJQh8WX4Z372du1KChsksyU") or sp.address("KT1AafHA1C1vk959wvHWBispY9Y2f3fxBUUo").
The address can carry an entrypoint name, for example: sp.address("KT1AafHA1C1vk959wvHWBispY9Y2f3fxBUUo%approve").