['literature', 'monsters', 'divide', 'archaeology', 'conspiracies']
Es necessita una funció en Swift que, donada una data en format "AAAA-MM-DD", retorni el dia de la setmana corresponent en català (dilluns, dimarts, etc.).
```swift
import Foundation

func diaDeLaSetmana(data: String) -> String? {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd"

    if let date = dateFormatter.date(from: data) {
        let calendar = Calendar.current
        let weekday = calendar.component(.weekday, from: date)

        let diesSetmana = ["diumenge", "dilluns", "dimarts", "dimecres", "dijous", "divendres", "dissabte"]
        return diesSetmana[weekday - 1]
    } else {
        return nil
    }
}
```