如何在两个QListWidgets之间移动项目？

from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QListWidget, QPushButton, QHBoxLayout
from PyQt5.QtCore import Qt, QMimeData
from PyQt5.QtGui import QDrag

class DragListWidget(QListWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setAcceptDrops(True)

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

    def dragMoveEvent(self, event):
        if event.mimeData().hasFormat('text/plain'):
            event.setDropAction(Qt.MoveAction)
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        if event.mimeData().hasFormat('text/plain'):
            data = event.mimeData().text()
            item = QListWidgetItem(data, self)
            item.setFlags(Qt.ItemIsSelectable | Qt.ItemIsDragEnabled | Qt.ItemIsEnabled)
            event.setDropAction(Qt.MoveAction)
            event.accept()
        else:
            event.ignore()

class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        layout = QHBoxLayout()

        self.list1 = DragListWidget()
        self.list2 = DragListWidget()

        self.list1.addItem("Item 1")
        self.list1.addItem("Item 2")
        self.list1.addItem("Item 3")

        layout.addWidget(self.list1)
        layout.addWidget(self.list2)

        self.setLayout(layout)
        self.setWindowTitle('Drag and Drop Example')
        self.show()

if __name__ == '__main__':
    app = QApplication([])
    ex = Example()
    app.exec_()