如何在QListWidget中以编程方式退出拖放操作？

class MyListWidget(QtWidgets.QListWidget):
    def __init__(self, parent=None):
        super(MyListWidget, self).__init__(parent)

class MyListWidget(QtWidgets.QListWidget):
    def __init__(self, parent=None):
        super(MyListWidget, self).__init__(parent)

    def dragEnterEvent(self, event):
        if event.mimeData().hasFormat('text/plain'):
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        text = event.mimeData().text()
        item = QtWidgets.QListWidgetItem(text)
        self.addItem(item)

app = QtWidgets.QApplication(sys.argv)
list_widget = MyListWidget()
list_widget.setAcceptDrops(True)
list_widget.show()
sys.exit(app.exec_())