PyQt5使用QFileDialog将QlineEdit保存到文本文件

我正在尝试通过QFileDialog创建具有保存功能的GUI。但是，每次我尝试保存时，它都会自行终止。

这是我通过按钮传递的函数的代码。

def saveInput(self):   

    name = QtWidgets.QFileDialog.getSaveFileName(MainWindow, "Save File", '/', '.txt')
    file = open(name, 'w')
    text = self.lineEdit.text()
    file.write(text)
    file.close()   

这是整个代码：

from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QFileDialog

class Ui_MainWindow(object):


    def saveInput(self):   

        name = QtWidgets.QFileDialog.getSaveFileName(MainWindow, "Save File", '/', '.txt')
        file = open(name, 'w')
        text = self.lineEdit.text()
        file.write(text)
        file.close()    


    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(431, 275)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")


        self.save = QtWidgets.QPushButton(self.centralwidget)
        self.save.setGeometry(QtCore.QRect(70, 140, 75, 23))
        self.save.setObjectName("save")
        self.save.clicked.connect(self.saveInput)        

        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(70, 20, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit.text()


        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 431, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)


    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.save.setText(_translate("MainWindow", "Save"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())