Generics Array problem

[oncity]

json data
{"dateline":123,"data":[{"tid":1466218037,"subject":"time is"},{"tid":123,"subject":"catcat"}]}

class NewsNode: Mappable {
    var tid: Int?
    var subject: String?
    required init?(_ map: Map) {
    }

    func mapping(map: Map) {
        tid    <- map["tid"]
        subject <- map["subject"]
    }
}


class BaseList<T>: Mappable {
    var dateline: Int?
    var data: [T]?
    required init?(_ map: Map) {
    }

    func mapping(map: Map) {
        dateline <- map["dateline"]
        data <- map["data"]
    }
}


        Alamofire.request(.GET, URL).responseObject { (response: Response< BaseList<NewsNode>, NSError>) in
            let dd = response.result.value
            print(dd?.data)
        }

data is nil

if change to
var data: [NewsNode]?
is work

help

[oncity]

have fix

class BaseList<T:Mappable>: Mappable