class ThreadHandler(QThread):

    def __init(self, parent=None):
        super(ThreadHandler, self).__init__(parent)
        self.threads = []
        self.active_threads = []
        self.running = False

    def add_thread(self, thread):
        self.threads.append(thread)

    def run(self):

        if not self.running:
            self.running = True
            index = 0

            while self.running:
                for i in range(index, index+3):
                    self.active_threads.append(self.threadcheck[i])
                    self.activethreads[i].start()

                while not self.threadcheck():
                    pass

    def threadcheck(self, *args):
        for _thread in args:
            if not _thread.isFinished():
                return False