class Yoba(QtCore.QObject):

    progress = QtCore.pyqtSignal(str)
    finished = QtCore.pyqtSignal()

    def __init__(self):

        super().__init__()

        self.thread = QtCore.QThread()
        self.moveToThread(self.thread)
        self.finished.connect(self.thread.quit)
        self.thread.started.connect(self.run)
        self.thread.start()

    def stop(self):

        self.stopped = True

    @QtCore.pyqtSlot()
    def run(self):

        while not self.stopped:

            # work

        self.finished.emit()