Drag and Drop for QTreeView not Working on Mac OS X

import sys
from PySide2 import QtWidgets, QtGui, QtCore

class TreeModel(QtCore.QAbstractItemModel):
    def __init__(self):
        QtCore.QAbstractItemModel.__init__(self)
        self.nodes = ['node0', 'node1', 'node2']    def index(self, row, column, parent):
        return self.createIndex(row, column, self.nodes[row])    def parent(self, index):
        return QtCore.QModelIndex()    def rowCount(self, index):
        if index.internalPointer() in self.nodes:
            return 0
        return len(self.nodes)    def columnCount(self, index):
        return 1    def data(self, index, role):
        if role == 0:
            return index.internalPointer()
        else:
            return None    def supportedDropActions(self):
        return QtCore.Qt.CopyAction | QtCore.Qt.MoveAction            def flags(self, index):
        if not index.isValid():
            return QtCore.Qt.ItemIsEnabled
        return QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable | \
               QtCore.Qt.ItemIsDragEnabled | QtCore.Qt.ItemIsDropEnabled            def mimeTypes(self):
        return ['text/xml']    def mimeData(self, indexes):
        mimedata = QtCore.QMimeData()
        mimedata.setData('text/xml', b'mimeData')
        return mimedata    def dropMimeData(self, data, action, row, column, parent):
        print('dropMimeData %s %s %s %s' % (data.data('text/xml'), action, row, parent))
        return True

class MainForm(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainForm, self).__init__(parent)        self.treeModel = TreeModel()        self.view = QtWidgets.QTreeView()
        self.view.setModel(self.treeModel)
        self.view.setDragDropMode(QtWidgets.QAbstractItemView.InternalMove)        self.setCentralWidget(self.view)def main():
    app = QtWidgets.QApplication(sys.argv)
    form = MainForm()
    form.show()
    app.exec_()if __name__ == '__main__':
    main()