python pyqt5 From窗口内嵌子窗口

效果展示

实现功能：
1.点击打开窗体实现子窗口内嵌主窗口展示
2.通过文件控件内的open控件导入文本内容在子窗口展示
3.通过文件控件内的close实现子窗口关闭

代码：

# -*- coding: utf-8 -*-
# Created by: PyQt5 UI code generator 5.6
# WARNING! All changes made in this file will be lost!
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication,QMainWindow,QWidget,QFileDialog

class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(700,550)
        self.textEdit = QtWidgets.QTextEdit(Form)
        self.textEdit.setGeometry(QtCore.QRect(70, 50, 491, 281))
        self.textEdit.setObjectName("textEdit")
        self.textEdit.setStyleSheet("background-color:#FFFFFF;color: rgb(0,0,0);font: 15pt \"AcadEref\";")

        self.retranslateUi(