self.Licensekey.setObjectName("Licensekey")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)

        self.pushButton.setGeometry(QtCore.QRect(160, 120, 101, 21))

        self.pushButton.setObjectName("pushButton")

        self.Username = QtWidgets.QLineEdit(self.centralwidget)

        self.Username.setGeometry(QtCore.QRect(160, 40, 113, 20))

        self.Username.setObjectName("Username")

self.Password = QtWidgets.QLineEdit(self.centralwidget)

        self.Password.setGeometry(QtCore.QRect(290, 40, 113, 20))

        self.Password.setObjectName("Password")

I am using these functions now to save and open files:

def file_save(self):

        name = QtGui.QFileDialog.getSaveFileName(self, 'Save File')

        file = open(name,'w')

        text = self.textEdit.toPlainText()

        file.write(text)

        file.close()

    def file_open(self):

        name = QtGui.QFileDialog.getOpenFileName(self, 'Open File')

        file = open(name,'r')

        self.editor()

        with file:

            text = file.read()

            self.textEdit.setText(text)