gistfile1.txt

extension Array where Element: ComparisonProtocol {
    func unique() -> [Element] {
        var uniqVals2: Set<String> = []
        return self.filter {
            guard let comparisonAttribute = $0.comparisonAttribute else { return false }
            
            if uniqVals2.contains(comparisonAttribute) == false {
                uniqVals2.insert(comparisonAttribute)
                return true
            }
            return false
        }
    }
}