pass arguments to function in python using command line in kali

I have a basic code just 3 lines written in python

import sys 
    def add(a, b):
        print("Result", a + b)

I want to pass value to a and b and print the result using commend line in kali I have tried

python3 a.py add 1 2

python3 a.py add (1, 2)

but non work. Any suggestions?