let numbers = [1,2,3,4]
        let result = numbers.map { $0 + 2 }
        let result2 = numbers.flatMap { $0 + 2 }
        print(result,result2)  // [3,4,5,6]
        let numbersCompound = [[1,3],[4,6]];
        let flatRes = numbersCompound.flatMap { $0.map{ $0} }
        let filteredArray = flatRes.filter({$0 > 5})