Как добавить неограниченное количество виджетов?

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QWidget, QMainWindow
 
 
class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(402, 346)
 
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
 
        self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea.setGeometry(QtCore.QRect(120, 40, 201, 80))
        self.scrollArea.setWidgetResizable(True)
        self.scrollArea.setObjectName("scrollArea")
        self.scrollAreaWidgetContents = QtWidgets.QWidget()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 199, 78))
        self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
 
        self.verticalLayoutWidget = QtWidgets.QWidget(self.scrollAreaWidgetContents)
        self.verticalLayoutWidget.setGeometry(QtCore.QRect(0, 0, 201, 80))
        self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
 
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
 
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(170, 130, 111, 23))
        self.pushButton.setObjectName("pushButton")
 
        MainWindow.setCentralWidget(self.centralwidget)
 
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 402, 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.pushButton.setText(_translate("MainWindow", "Добавь кнопку"))
 
 
class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self):
        super().__init__()
        self.setupUi(self)
        self.main()
    
    def main(self):
        self.pushButton.clicked.connect(self.addPushButton)
    
    def addPushButton(self):
        _translate = QtCore.QCoreApplication.translate
 
        self.newPushButton = QtWidgets.QPushButton(self.centralwidget)
        self.newPushButton.setObjectName("newPushButton")
        self.newPushButton.setText(_translate('MainWindow', 'Кнопка'))
 
        self.verticalLayout.addWidget(self.newPushButton)
 
 
app = QtWidgets.QApplication(sys.argv)
ex = MainWindow()
ex.show()
sys.exit(app.exec_())

import sys
from PyQt5.QtWidgets import *
 
class App(QWidget):
 
    def __init__(self):
        super().__init__()
        self.title = 'PyQt51.04'
        self.left = 100
        self.top = 100
        self.width = 320
        self.height = 200
        self.i = 0
        self.initUI()
    
    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
 
        self.scrollArea = QScrollArea()
        self.scrollArea.setWidgetResizable(True)
        self.layout = QGridLayout()
        
        button = QPushButton('PyQt5 button', self)
        button.clicked.connect(self.on_click)
        button.setFixedHeight(24)
 
        self.layout.addWidget(button, self.i, 0)
 
        self.inner = QFrame(self.scrollArea)
        self.inner.setLayout(self.layout)
        self.scrollArea.setWidget(self.inner)
 
        layout = QVBoxLayout()
        layout.addWidget(self.scrollArea)
        self.setLayout(layout)
        self.show()
 
    def on_click(self):
        self.i += 1
        button = QPushButton('PyQt5 button', self)
        button.setFixedHeight(24)
        self.inner.layout().addWidget(button, self.i, 0)
 
 
if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())