 		self.values = [:]
 		extend(sequence)
 	}
-	
+
 	public init() {
 		self.values = [:]
 	}
-	
+
 	public init(minimumCapacity: Int) {
 		self.values = [Element:Unit](minimumCapacity: minimumCapacity)
 	}

extension Set: Printable {
	public var description: String {
		if self.count == 0 { return "{}" }
		
		let joined = join(", ", map(toString))
		return "{ \(joined) }"
	}

	public func contains(element: Element) -> Bool {
		return values[element] != nil
	}

	public mutating func insert(element: Element) {
		values[element] = Unit()
	}

	public mutating func remove(element: Element) {
		values.removeValueForKey(element)
	}
