Pre lenku :D

    static func downloadBranch(_ groupParentId: Int, finished: @escaping ([GroupModel]) -> ()) {
        var groupList = [GroupModel]()
        FlipDataMapper.getGroup(groupParentId, completed: { (group) in
            groupList.append(group!)
            FlipDataMapper.getGroup((group?.parentId)!, completed: { (group) in
                groupList.append(group!)
                FlipDataMapper.getGroup((group?.parentId)!, completed: { (group) in
                    groupList.append(group!)
                    finished(groupList)
                    print("Job's finished")
                })
            })
        })
    }

    static func downloadAllOriginalBranches(listOfFlips: [FlipModel], finished: @escaping ([GroupModel]) -> ()) {
        var groupList = [GroupModel]()
        let myGroup = DispatchGroup()

        for flip in listOfFlips {
            myGroup.enter()
            FlipDataMapper.downloadBranch(flip.parentId!, finished: { (group) in
                groupList.append(contentsOf: group)
                finished(groupList)
                print("Job's finished")
                myGroup.leave()
            })
        }
        myGroup.notify(queue: .main) {
            print("Finished all requests.")
            finished(groupList)
        }
    }