     }
     
     func getGroupCoordinator(groupId: String, callback: @escaping (Broker) -> Void) {
-        _brokers.first?.value.getGroupCoordinator(groupId: groupId) { response in
+        brokers.first?.value.getGroupCoordinator(groupId: groupId) { response in
             let host = response.host
             let port = response.port
             

        - Parameter callback:
     */
    public func listGroups(_ callback: @escaping (String, String) -> ()) {
        for (_, broker) in _brokers {
            dispatchQueue.async {
                broker.listGroups() { a, b in
                    callback(a, b)

                return
            }
            
            if let broker = self.brokers["\(host):\(port)"] {
                callback(broker)
            } else {
                print("Broker: \(host):\(port) Not Found.")
