Help with "Functions in Swift"-challenge

The text says:

In this challenge, we have the following geographical coordinates

Eiffel Tower - lat: 48.8582, lon: 2.2945 Great Pyramid - lat: 29.9792, lon: 31.1344 Sydney Opera House - lat: 33.8587, lon: 151.2140

Declare a function named coordinates that takes a single parameter of type String, with an external name for, a local name of location, and returns a tuple containing two Double values (Note: You do not have to name the return values). For example, if I use your function and pass in the string "Eiffel Tower" as an argument, I should get (48.8582, 2.2945) as the value. If a string is passed in that doesn’t match the set above, return (0,0) Bummer! Make sure you accept a single parameter of type String in your function declaration with the correct argument labels.

Please see my code below. Why is it not working? :)

// Enter your code below
func coordinates(location: String) -> (Double, Double) {

    var coordinates: (Double, Double) = (0,0)

    switch location {
        case "Eiffel Tower": coordinates = (48.8582, 2.2945)
        case "Great Pyramid": coordinates = (29.9792, 31.1344)
        case "Sydney Opera House": coordinates = (33.8587, 151.2140)
    default: coordinates = (0,0)
    }
    return coordinates
}

coordinates("Eiffel Tower")