如何在Python PyQt5的QTreeView中添加过滤器功能

Question

我编写的这段代码未能为QTreeView创建过滤器功能，请帮助我如何在TreeView中添加过滤器，如下图所示。

import os
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
#from PyQt5.QtWidgets import QApplication, QFileSystemModel, QTreeView, QWidget, QVBoxLayout,QPushButton, QMessageBox,QDialog,QTableWidget,QTabWidget

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):


        self.treeWidget_2.setObjectName("treeWidget_2")
        #self.treeWidget_2.headerItem().setText(0, "1")
        self.gridLayout_2.addWidget(self.treeWidget_2, 1, 0, 1, 1)

        self.model = QtWidgets.QFileSystemModel()
        #self.model.setFilter(QtCore.QDir.Files) 
        self.model.setRootPath('')

        self.treeWidget_2.setModel(self.model)
        #m = self.treeWidget_2.selectionModel()
        #m.selectionChanged.connect(self.onSelectionChanged)
        self.treeWidget_2.setAnimated(True)
        #self.treeWidget_2.setAlternatingRowColors(True)
        self.treeWidget_2.setIndentation(25)
        self.treeWidget_2.setSortingEnabled(True)
        self.treeWidget_2.setWindowTitle("Dir View")

        self.lineEdit = QtWidgets.QLineEdit(self.dockWidgetContents_5)
        self.lineEdit.setObjectName("lineEdit")
        self.gridLayout_2.addWidget(self.lineEdit, 0, 0, 1, 1)

        #------------------

        self.model = QtGui.QStandardItemModel(self.treeWidget_2)
        self.proxyModel = QtCore.QSortFilterProxyModel(self.treeWidget_2)
        self.proxyModel.setSourceModel(self.model)
        self.treeWidget_2.setSortingEnabled(True)

        # set model
        self.treeWidget_2.setModel(self.proxyModel)
        #self.treeWidget_2.clicked.connect(self.update_model)
        self.lineEdit.textChanged.connect(self.onTextChanged)

 #@QtCore.pyqtSlot(str)
    def onTextChanged(self, text):
        self.proxyModel.setFilterRegExp(text)