Get none from this function, why?

Question

alder = int(input("Din alder: "))
reiserute = int(input("Hvilken reiserute: "))


def bilett_pris(alder, reiserute):

    if alder <= 2:
        return 0

        rutepristabell = {
            "rute1": 150,
            "rute2": 250,
            "rute3": 50,
        }

        rutepris = rutepristabell[reiserute]

        alder_rabatt = 0.65
        if alder <= 65:
            alder_rabatt = 0
        if alder <= 16:
            alder_rabatt = 0.5

            return rutepris - rutepris * alder_rabatt

print(bilett_pris(alder, reiserute))

Answer 1

A function that does not reach any other return statement implicitly returns None.

Python is an indentation sensitive language. There are two indentation problems in your code.

Firstly, looking at the start of your function

    if alder <= 2:
        return 0

        rutepristabell = {
            ...

you can see that the entire function body is inside the alder <= 2 block. Since the first statement of that block is a return, the rest of the function is unreachable.

Secondly, near the end,

       if alder <= 16:
            alder_rabatt = 0.5

            return rutepris - rutepris * alder_rabatt

the other return is also misindented to be inside the other if, so even if you did fix the first issue, you'd only ever reach a return if alder <= 16.

The correct indentation is

def bilett_pris(alder, reiserute):

    if alder <= 2:
        return 0

    rutepristabell = {
        "rute1": 150,
        "rute2": 250,
        "rute3": 50,
    }

    rutepris = rutepristabell[reiserute]

    alder_rabatt = 0.65
    if alder <= 65:
        alder_rabatt = 0
    if alder <= 16:
        alder_rabatt = 0.5

    return rutepris - rutepris * alder_rabatt   

and as you can see, there's always a definite return now.