how can we write or condition inside method argument?

Hi all, i am beginner to py,

I have a method like below.
def method(input1 or input2)
and I have 2 inputs input1 and input2.

User should select only one input from here.. input1 or input2 and based on user input that should be passed on as method argument. Here my question is - how can we write or condition inside method argument?