Swift-在字典中插入数组数据

Question

我需要存储的当前数据是这样的

var dictData = [String: [String]] () 

[groupIdKey : [key1,key2], groupIdKey2 : [key3,key4] ]

如何将[key1，key2]插入特定的字典键，以及如何访问该dictData变量中的每个键？

我正在使用Firebase数据库，这是我的代码

let groupId = self.defaults.stringArray(forKey: Constants.localDataKeys.localDataGroupId)
var addValueDict = [String: [Any]]() as NSDictionary
for group in groupId! {
    geoLocRef.child("Group").child("\(group)").child("groupMembers").observeSingleEvent(of: .value, with: { (snapshot) in
        if(snapshot.value as? [String: AnyObject]) == nil {
            print("Gada group *geolocation*")
        } else {
            let memberIdDict = snapshot.value as! [String: Any]
            let getGroupMemberId = Array(memberIdDict.keys)
             // addValueDict["\(group)"]?.append([getGroupMemberId]) <-- My Error
        }
    })
} // end for loop NSUserDefaults