EnumerationComputedProperty.swift

enum Month {
    case January
    case February
    case March
    case April
    case May
    case June
    case July
    case August
    case September
    case October
    case November
    case December
    
    var season: String {
        switch self {
            case Month.December, Month.January, Month.February:
                return "Winter"
            case Month.March, Month.April, Month.May:
                return "Spring"
            case Month.June, Month.July, Month.August:
                return "Summer"
            case Month.September, Month.October, Month.November:
                return "Autumn"
        }
    }
}