Python3.7.6とPyQt5を使ってuiファイルをロードする。

import sys
from PyQt5 import QtWidgets, uic
from PyQt5.QtGui import QPixmap
import pityna
import responder


#class MainWindow(QtWidgets.QMainWindow):
class MainWindow():
    def __init__(self):
        #super().__init__()
        self.pityna=pityna.Pityna('pityna')
        self.action=True
        #self.ui = uic.loadUi("../../qt_Pityna_Simple.ui")
        self.ui = uic.loadUi("qt_Pityna_Simple.ui")
        self.ui.label_2.setPixmap(QPixmap("img1.gif"))
        self.slotSetting()
        self.ui.show()        
    def slotSetting(self):
        self.ui.buttonTalk.clicked.connect(self.buttonTalkSlot)
        self.ui.radioButton.clicked.connect(self.showResponderName)
        self.ui.radioButton_2.clicked.connect(self.HideResponderName)
        self.ui.menuClose.triggered.connect(self.close)
    def putlog(self,str):
        self.ui.listWidgetLog.addItem(str)
    def prompt(self):
        p=self.pityna.get_name()
        if self.action==True:
            p+=':'+self.pityna.get_responder_name()
        return p+'> '
    def buttonTalkSlot(self):
        print("buttonTalkSlot")
        value= self.ui.lineEdit.text()
        if not value:
            self.ui.labelResponce.setText('なに？')
        else:
            responce=self.pityna.dialogue(value)
            self.ui.labelResponce.setText(responce)
            self.putlog('> '+value)
            self.putlog(self.prompt() + responce)
            self.ui.lineEdit.clear()
    def showResponderName(self):
        print("showResponderName")
        self.action=True
    def HideResponderName(self):
        print("HideResponderName")
        self.action=False
    def close(self):
        replay = QtWidgets.QMessageBox.question(
            self.ui, 
            '確認', 
            'プログラムを終了しますか？',
            buttons=QtWidgets.QMessageBox.Yes | 
                    QtWidgets.QMessageBox.No
            )
        if replay==QtWidgets.QMessageBox.Yes:
            #event.accept()
            self.ui.close()
        else:
            #event.ignore()
            pass
        
app = QtWidgets.QApplication(sys.argv)
MainWindow=MainWindow()
ret=app.exec()
sys.exit(ret)