Question

I want to change a python function to return two values. How do I achieve that without affecting any of the previous function calls which only expect one return value?

For eg.

Original Definition:

def foo():
    x = 2
    y = 2
    return (x+y)

sum = foo()

Ne Definition:

def foo():
    x = 2
    y = 2
   return (x+y), (x-y)

sum, diff = foo()

I want to do this in a way that the previous call to foo also remains valid?
Is this possible?

Answer 1

def foo(return_2nd=False):

    x = 2
    y = 2
    return (x+y) if not return_2nd else (x+y),(x-y)

then call new version

sum, diff = foo(True)
sum = foo() #old calls still just get sum