求助PyQt5大神，.ui文件生成的.py代码怎么才能运行？

[MOM_k]

这段代码是用.ui文件生成的.py文件，请问要怎么才能运行起来看到界面？

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'mainwindow.ui'
#
# Created by: PyQt5 UI code generator 5.11.3
#
# WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets
import sys

class Ui_MainWindow(object):

    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(100, 5, 371, 231))
        self.gridLayoutWidget.setObjectName("gridLayoutWidget")
        self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.setContentsMargins(0, 0, 0, 0)
        self.gridLayout.setObjectName("gridLayout")
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.pushButton_3 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_3.setObjectName("pushButton_3")
        self.horizontalLayout.addWidget(self.pushButton_3)
        self.pushButton_2 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_2.setObjectName("pushButton_2")
        self.horizontalLayout.addWidget(self.pushButton_2)
        self.pushButton = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton.setObjectName("pushButton")
        self.horizontalLayout.addWidget(self.pushButton)
        self.gridLayout.addLayout(self.horizontalLayout, 0, 0, 1, 1)
        self.verticalLayout = QtWidgets.QVBoxLayout()
        self.verticalLayout.setObjectName("verticalLayout")
        self.pushButton_4 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_4.setObjectName("pushButton_4")
        self.verticalLayout.addWidget(self.pushButton_4)
        self.pushButton_5 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_5.setObjectName("pushButton_5")
        self.verticalLayout.addWidget(self.pushButton_5)
        self.pushButton_6 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_6.setObjectName("pushButton_6")
        self.verticalLayout.addWidget(self.pushButton_6)
        self.gridLayout.addLayout(self.verticalLayout, 1, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 23))
        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.pushButton_3.setText(_translate("MainWindow", "PushButton"))
        self.pushButton_2.setText(_translate("MainWindow", "PushButton"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))
        self.pushButton_4.setText(_translate("MainWindow", "PushButton"))
        self.pushButton_5.setText(_translate("MainWindow", "PushButton"))
        self.pushButton_6.setText(_translate("MainWindow", "PushButton"))

[极度缺钱]

if __name__ == "__main__":
import sys

app = QtWidgets.QApplication(sys.argv)
myshow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(myshow)
myshow.show()
sys.exit(app.exec_())