Having trouble opening multiple windows

I'm using PyQt5 designer to make a little application. I mostly work with designer rather than building from scratch so this might be a silly question. Basically i have a main menu and a "create" button that when clicked will open up the other pyqt5 .py file (also created in designer) i have been working on.

So far i complied the ui files into .py files and imported the popup window that i want to be able to generate more than one of and then i use this code to some success:

I have not added any additonal code to the converted ui files excpect this function:

Here is some code from my mainmenu and popoutwindow .py files:

this is the setupUi being called from my file im trying to replicate

class BookPopout(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(772, 685)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lastNameLabel = QtWidgets.QLabel(self.centralwidget)
        self.lastNameLabel.setGeometry(QtCore.QRect(20, 110, 60, 17))
        self.lastNameLabel.setObjectName("lastNameLabel")
        self.cityEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.cityEntry.setGeometry(QtCore.QRect(20, 310, 391, 27))
        self.cityEntry.setReadOnly(True)
        self.cityEntry.setObjectName("cityEntry")
        self.bookTable = QtWidgets.QTableWidget(self.centralwidget)
        self.bookTable.setGeometry(QtCore.QRect(470, 10, 281, 481))
        font = QtGui.QFont()
        font.setPointSize(7)
        self.bookTable.setFont(font)
        self.bookTable.setAutoFillBackground(False)
        self.bookTable.setEditTriggers(QtWidgets.QAbstractItemView.NoEditTriggers)
        self.bookTable.setRowCount(1)
        self.bookTable.setColumnCount(1)
        self.bookTable.setObjectName("bookTable")
        item = QtWidgets.QTableWidgetItem()
        self.bookTable.setItem(0, 0, item)
        self.bookTable.horizontalHeader().setVisible(False)
        self.bookTable.horizontalHeader().setCascadingSectionResizes(False)
        self.bookTable.horizontalHeader().setDefaultSectionSize(100)
        self.bookTable.horizontalHeader().setStretchLastSection(True)
        self.addressLineOneEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.addressLineOneEntry.setGeometry(QtCore.QRect(20, 190, 391, 27))
        self.addressLineOneEntry.setReadOnly(True)
        self.addressLineOneEntry.setObjectName("addressLineOneEntry")
        self.stateEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.stateEntry.setGeometry(QtCore.QRect(20, 380, 391, 27))
        self.stateEntry.setReadOnly(True)
        self.stateEntry.setObjectName("stateEntry")
        self.firstNameEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.firstNameEntry.setGeometry(QtCore.QRect(20, 70, 391, 27))
        self.firstNameEntry.setReadOnly(True)
        self.firstNameEntry.setObjectName("firstNameEntry")
        self.streetAddressLabel = QtWidgets.QLabel(self.centralwidget)
        self.streetAddressLabel.setGeometry(QtCore.QRect(20, 170, 83, 17))
        self.streetAddressLabel.setObjectName("streetAddressLabel")
        self.streetAddressTwoLabel = QtWidgets.QLabel(self.centralwidget)
        self.streetAddressTwoLabel.setGeometry(QtCore.QRect(20, 240, 220, 17))
        self.streetAddressTwoLabel.setObjectName("streetAddressTwoLabel")
        self.phoneNumberLabel = QtWidgets.QLabel(self.centralwidget)
        self.phoneNumberLabel.setGeometry(QtCore.QRect(20, 480, 87, 17))
        self.phoneNumberLabel.setObjectName("phoneNumberLabel")
        self.addressLineTwoEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.addressLineTwoEntry.setGeometry(QtCore.QRect(20, 260, 391, 27))
        self.addressLineTwoEntry.setReadOnly(True)
        self.addressLineTwoEntry.setObjectName("addressLineTwoEntry")
        self.phoneNumberEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.phoneNumberEntry.setGeometry(QtCore.QRect(20, 500, 391, 27))
        self.phoneNumberEntry.setReadOnly(True)
        self.phoneNumberEntry.setObjectName("phoneNumberEntry")
        self.firstNameLabel = QtWidgets.QLabel(self.centralwidget)
        self.firstNameLabel.setGeometry(QtCore.QRect(20, 40, 62, 17))
        self.firstNameLabel.setObjectName("firstNameLabel")
        self.cityLabel = QtWidgets.QLabel(self.centralwidget)
        self.cityLabel.setGeometry(QtCore.QRect(20, 290, 23, 17))
        self.cityLabel.setObjectName("cityLabel")
        self.stateLabel = QtWidgets.QLabel(self.centralwidget)
        self.stateLabel.setGeometry(QtCore.QRect(20, 350, 29, 17))
        self.stateLabel.setObjectName("stateLabel")
        self.zipEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.zipEntry.setGeometry(QtCore.QRect(20, 440, 391, 27))
        self.zipEntry.setReadOnly(True)
        self.zipEntry.setObjectName("zipEntry")
        self.zipLabel = QtWidgets.QLabel(self.centralwidget)
        self.zipLabel.setGeometry(QtCore.QRect(20, 410, 18, 17))
        self.zipLabel.setObjectName("zipLabel")
        self.emailEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.emailEntry.setGeometry(QtCore.QRect(20, 550, 391, 27))
        self.emailEntry.setObjectName("emailEntry")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(20, 530, 80, 17))
        self.label.setObjectName("label")
        self.confirmNewPersonButton = QtWidgets.QPushButton(self.centralwidget)
        self.confirmNewPersonButton.setGeometry(QtCore.QRect(20, 590, 85, 27))
        self.confirmNewPersonButton.setObjectName("confirmNewPersonButton")
        self.lastNameEntry = QtWidgets.QLineEdit(self.centralwidget)
        self.lastNameEntry.setEnabled(True)
        self.lastNameEntry.setGeometry(QtCore.QRect(20, 130, 391, 27))
        self.lastNameEntry.setText("")
        self.lastNameEntry.setReadOnly(True)
        self.lastNameEntry.setObjectName("lastNameEntry")
        self.sortComboBox = QtWidgets.QComboBox(self.centralwidget)
        self.sortComboBox.setGeometry(QtCore.QRect(500, 530, 101, 31))
        self.sortComboBox.setObjectName("sortComboBox")
        self.sortByLabel = QtWidgets.QLabel(self.centralwidget)
        self.sortByLabel.setGeometry(QtCore.QRect(570, 500, 71, 31))
        font = QtGui.QFont()
        font.setPointSize(14)
        self.sortByLabel.setFont(font)
        self.sortByLabel.setObjectName("sortByLabel")
        self.sortButton = QtWidgets.QPushButton(self.centralwidget)
        self.sortButton.setGeometry(QtCore.QRect(600, 530, 111, 31))
        font = QtGui.QFont()
        font.setPointSize(14)
        self.sortButton.setFont(font)
        self.sortButton.setObjectName("sortButton")
        self.addNewPersonButton = QtWidgets.QPushButton(self.centralwidget)
        self.addNewPersonButton.setGeometry(QtCore.QRect(40, 10, 101, 27))
        self.addNewPersonButton.setObjectName("addNewPersonButton")
        self.editEntryButton = QtWidgets.QPushButton(self.centralwidget)
        self.editEntryButton.setGeometry(QtCore.QRect(170, 10, 111, 27))
        self.editEntryButton.setObjectName("editEntryButton")
        self.confirmEditButton = QtWidgets.QPushButton(self.centralwidget)
        self.confirmEditButton.setGeometry(QtCore.QRect(20, 590, 111, 27))
        self.confirmEditButton.setObjectName("confirmEditButton")
        self.deleteEntryButton = QtWidgets.QPushButton(self.centralwidget)
        self.deleteEntryButton.setGeometry(QtCore.QRect(300, 10, 111, 27))
        self.deleteEntryButton.setObjectName("deleteEntryButton")
        self.sortByLabel_2 = QtWidgets.QLabel(self.centralwidget)
        self.sortByLabel_2.setGeometry(QtCore.QRect(530, 570, 131, 31))
        font = QtGui.QFont()
        font.setPointSize(12)
        self.sortByLabel_2.setFont(font)
        self.sortByLabel_2.setObjectName("sortByLabel_2")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(500, 600, 101, 31))
        self.lineEdit.setObjectName("lineEdit")
        self.sortButton_2 = QtWidgets.QPushButton(self.centralwidget)
        self.sortButton_2.setGeometry(QtCore.QRect(600, 600, 111, 31))
        font = QtGui.QFont()
        font.setPointSize(14)
        self.sortButton_2.setFont(font)
        self.sortButton_2.setObjectName("sortButton_2")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setEnabled(True)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 772, 27))
        self.menubar.setObjectName("menubar")
        self.menuOpen = QtWidgets.QMenu(self.menubar)
        self.menuOpen.setObjectName("menuOpen")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.actionSave = QtWidgets.QAction(MainWindow)
        self.actionSave.setObjectName("actionSave")
        self.actionSave_as = QtWidgets.QAction(MainWindow)
        self.actionSave_as.setObjectName("actionSave_as")
        self.actionClose = QtWidgets.QAction(MainWindow)
        self.actionClose.setObjectName("actionClose")
        self.menuOpen.addAction(self.actionSave)
        self.menuOpen.addSeparator()
        self.menuOpen.addAction(self.actionSave_as)
        self.menuOpen.addSeparator()
        self.menuOpen.addAction(self.actionClose)
        self.menubar.addAction(self.menuOpen.menuAction())
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

Here is my mainmenu py file:

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(255, 410)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.createNewBookButton = QtWidgets.QPushButton(self.centralwidget)
        self.createNewBookButton.setGeometry(QtCore.QRect(40, 220, 171, 41))
        self.createNewBookButton.setObjectName("createNewBookButton")
        self.createNewBookButton.clicked.connect(self.openNewBook)

        self.openExistingBookButton = QtWidgets.QPushButton(self.centralwidget)
        self.openExistingBookButton.setGeometry(QtCore.QRect(40, 280, 171, 41))
        self.openExistingBookButton.setObjectName("openExistingBookButton")
        self.quitProgramButton = QtWidgets.QPushButton(self.centralwidget)
        self.quitProgramButton.setGeometry(QtCore.QRect(40, 340, 171, 41))
        self.quitProgramButton.setObjectName("quitProgramButton")
        self.mainImage = QtWidgets.QGraphicsView(self.centralwidget)
        self.mainImage.setGeometry(QtCore.QRect(10, 10, 231, 192))
        self.mainImage.setObjectName("mainImage")
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def openNewBook(self):
        self.popWin = QtWidgets.QMainWindow()
        self.bookUI = bookPopout.BookPopout()
        self.bookUI.setupUi(self.popWin)
        self.popWin.show()  

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

This works great for opening up ONE extra window, which stays open while my main window is open which is what i want, but then when i go to click to make another window appear, it just replaces the one i already had up, so i can only seem to have one extra at a time.

I figure that my old window is being referenced by self.popWin , and then being replaced over and over so my question i guess is what is the best way to go about "generating" windows instead of just referencing the same window over and over.. i tried to remove the "self" part but then the window just dosent even appear when i go to create a new window so i am kind of lost

for example i would expect to be able to write something like this but im not really sure how to go about doing so

currentWindows = []

newPopWin = QtWidgets.QMainWindow()
newBookUI = BookPopout()
newBookUI.setupUi(newPopWin)
newPopWin.show()

currentWindows.append(newPopWin)

this would be ideal so i could keep track of all current open windows so i may terminate them all once i close my main menu.

Any help would be appreciated to put me on the right track, i have tried looking up solutions but lots of examples are not using code converted from a UI file.

The problem is simple, we are overwriting an attribute and at that moment the previous element is deleted, for that reason only a window. As you point out the solution is to store it in a list.

But before that, I recommend you not to write your logic in the .py generated by Qt Designer since for example let's say that you want to modify something of the design, then when generating the new .py it will erase all your logic. What PyQt recommends is to use create another file where you generate the logic adviritiendote with the message: # WARNING! All changes made in this file will be lost!. So restore the previous files I called bookPopup.py and mainmenu.py by removing the openNewBook. Following the docs recommendation we obtain the following:

main.py

from PyQt5 import QtCore, QtGui, QtWidgets

import bookPopout
import mainmenu


class BookPopoutWindow(QtWidgets.QMainWindow, bookPopout.BookPopout):
    def __init__(self, parent=None):
        super(BookPopoutWindow, self).__init__(parent)
        self.setupUi(self)


class MainMenu(QtWidgets.QMainWindow, mainmenu.Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainMenu, self).__init__(parent)
        self.setupUi(self)
        self.createNewBookButton.clicked.connect(self.openNewBook)
        self.popups = []

    @QtCore.pyqtSlot()
    def openNewBook(self):
        popWin = BookPopoutWindow()
        popWin.show()
        self.popups.append(popWin)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainMenu()
    w.show()
    sys.exit(app.exec_())