python if then statements

I'm fairly new to python and I need to figure out how to convert blocks like the one below to python:

iAppd(t)=if(t<fromd)then(0)else(if(t>fromd&t<tod)then(iApd)else(0))

What is the best way to accomplish this in python?

Any help that can be provided would be greatly appreciated.

Thanks in advance.