How to repeat or duplicate word in Swift by using extension

again.swift

/* Copyright (C) 2018 Xvezda <https://xvezda.com/> */
/* MIT License */
extension String {
    func again(count: Int, with: String=" ") -> String {
        if count <= 0 {  // Ignore when count is less then zero.
            return self
        }
        var stringBuilder = self
        for _ in 0..<count {
            stringBuilder.append(with+self)
        }
        return stringBuilder
    }
}

print("Hello".again(count: 2, with: ", "))  // Hello, Hello, Hello
print("Hi".again(count: 1))  // Hi Hi