[PyQt] I get a name Name Error: when calling a method inside a class

[radoo]

Hello,

I have a problem that I cannot resolve by myself. I am learning Python and Qt and I am trying to get the values of the buttons I push in the interface into a list, but I get a name Error message when reading the output of the method outside of the class. Here is the code:

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

# Form implementation generated from reading ui file 'C:\Users\hp\Desktop\PythonLearning\PyQt\Hang\Test_UI_two_buttons.ui'
#
# Created by: PyQt5 UI code generator 5.14.2
#
# WARNING! All changes made in this file will be lost!


from PyQt5 import QtCore, QtGui, QtWidgets


class UiMainWindow(object):
    def __init__(self):
        self.clicked_button = []
        self.main_window = main_window
        self.centralwidget = QtWidgets.QWidget(main_window)
        self.A_Button = QtWidgets.QPushButton(self.centralwidget)
        self.B_Button = QtWidgets.QPushButton(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(main_window)
        self.statusbar = QtWidgets.QStatusBar(main_window)

    def setupUi(self, _main__window_):
        _main__window_.setObjectName("MainWindow")
        _main__window_.setEnabled(True)
        _main__window_.resize(863, 600)
        font = QtGui.QFont()
        font.setFamily("MS Sans Serif")
        _main__window_.setFont(font)
        _main__window_.setWindowOpacity(1)
        self.centralwidget.setObjectName("centralwidget")
        self.A_Button.setGeometry(QtCore.QRect(143, 210, 251, 111))
        font = QtGui.QFont()
        font.setFamily("Modern")
        font.setPointSize(10)
        font.setBold(True)
        font.setItalic(True)
        font.setWeight(75)
        self.A_Button.setFont(font)
        self.A_Button.setAutoFillBackground(False)
        self.A_Button.setCheckable(False)
        self.A_Button.setObjectName("A_Button")
        self.B_Button.setGeometry(QtCore.QRect(400, 210, 251, 111))
        font = QtGui.QFont()
        font.setFamily("Modern")
        font.setPointSize(10)
        font.setBold(True)
        font.setItalic(True)
        font.setWeight(75)
        self.B_Button.setFont(font)
        self.B_Button.setObjectName("B_Button")
        _main__window_.setCentralWidget(self.centralwidget)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 863, 21))
        self.menubar.setObjectName("menubar")
        _main__window_.setMenuBar(self.menubar)
        self.statusbar.setObjectName("statusbar")
        _main__window_.setStatusBar(self.statusbar)

        self.retranslateUi(_main__window_)
        QtCore.QMetaObject.connectSlotsByName(_main__window_)

    def retranslateUi(self, main_window_):
        _translate = QtCore.QCoreApplication.translate
        main_window_.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.A_Button.setText(_translate("MainWindow", "A"))
        self.A_Button.setShortcut(_translate("MainWindow", "A"))
        self.B_Button.setText(_translate("MainWindow", "B"))
        self.B_Button.setShortcut(_translate("MainWindow", "B"))

        self.A_Button.clicked.connect(self.button_clicked)
        self.B_Button.clicked.connect(self.button_clicked)

    def button_clicked(self):
        button_ = main_window.sender().text()
        self.clicked_button.append(button_)
        return self.clicked_button

input_list = UiMainWindow().button_clicked()
print(input_list)




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

Error message:

Error:
Traceback (most recent call last):
  File "C:/Users/hp/PycharmProjects/PythonLearning/Test_UI_two_buttons.py", line 78, in <module>
    input_list = UiMainWindow().button_clicked()
  File "C:/Users/hp/PycharmProjects/PythonLearning/Test_UI_two_buttons.py", line 16, in __init__
    self.main_window = main_window
NameError: name 'main_window' is not defined

If I replace the button_clicked method with the following, and remove the method call outside (line 78-79, the code works as expected, but it is inside the class and I want the value returned outside. Here is the code:

def button_clicked(self):
    button_ = self.main_window.sender().text()
    self.clicked_button.append(button_)
    print(self.clicked_button)

I was pointed out to this thread https://stackoverflow.com/questions/5690...on-classes
What I learned from it, is the different types of variable assignment inside a class and I understand that somewhere I did a mistake, but I can't spot it by myself. I'm trying to solve this seemingly trivial problem since hours and I'm confused.
Here is an example I wrote, that works:

class Exercises():

    def __init__(self):
        self.string_variable = ""

    def example_method(self):
        self.string_variable = input("Whatever")
        return self.string_variable


output = Exercises().example_method()

print(output)

I simply don't get why the last code works and the first does not. Help much appreciated!