Enums and Optional Code Challenge: Code works in xCode, fails in Editor

The challenge is:

In the editor, you have a pretty complex dictionary representing a movie. It contains a nested dictionary, which itself contains an array of Strings as a value.

Your job is to assign the string containing the value for the lead actor (which for the sake of the example is at position 0 in the array) to the variable leadActor.

Since dictionaries return optional values, you will have to use an if let statement to unwrap each consecutive operation.

my code is

let movieDictionary = ["Spectre": ["cast": ["Daniel Craig", "Christoph Waltz", "Léa Seydoux", "Ralph Fiennes", "Monica Bellucci", "Naomie Harris"]]]

var leadActor: String = ""

if let movie = movieDictionary["Spectre"],
    let cast = movie["cast"] {
    let leadActor = cast[0]
}

In xcode this works just fine and returns Daniel Craig, but in the treehouse editor it says: Make sure you are retrieving the string at index 0 in the nested array

Whats the deal?