Sorting an array of Dictionaries in swift and getting operator can't be applied to Any

I am trying to sort an array of Dictionaries by their timeStamp value from newest to oldest

error: Binary operator '<' cannot be applied to two 'Any?' operands

timeStamp value is saved as an Int into the Dictionary:

timeStamp = inviteDict["timeStamp"] as? Int

Dictionary:

[
"type": "invite",
"complimentId": key,
"status": status,
"timeStamp": timeStamp!,
 "fromUser": user
]

Function - combines two arrays of tuples, I need to sort the array by timeStamp before passing via handler:

    func getInvitesAndCompliments(forUserId forId: String, handler: @escaping ([[String : Any]], Bool) -> ()){

            var invitesAndCompliments = [[String : Any]]()

            var invites = [[String : Any]]()

            var compliments = [[String : Any]]()

            getComplimentsReceived(forUserId: forId) { (complimentsDict, success) in
                invitesAndCompliments.removeAll()
                compliments = complimentsDict
                invitesAndCompliments = invites + compliments
                handler(invitesAndCompliments, true)
            }

            getInvitesReceived(forUserId: forId) { (invitesDict, success) in
                invitesAndCompliments.removeAll()
                invites = invitesDict
                invitesAndCompliments = compliments + invites

                //sort array by timeStamp value
                let sorted_invitesAndCompliments = invitesAndCompliments.sorted(by: { $0["timeStamp"] < $1["timeStamp"] })

                handler(sorted_invitesAndCompliments, true)
            }


        }//end func