How to add items to combobox at runtime

Question

Im using Pyqt5 in python and i try to add itmes to combobox at runtime but its not showing unless i restart the program so here is my qestion how to add it dynamiclly

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys

class Window(QMainWindow):
    item_list=["a","b","c"]

    def __init__(self):
        super().__init__()
        self.setWindowTitle("Title")
        self.setGeometry(100, 100, 600, 400)
        self.ui_components() 
        self.show()

    def ui_components(self):
        combo_box = QComboBox(self)
        combo_box.setGeometry(10, 70, 100, 30)
        combo_box.currentTextChanged.connect(self.on_changed)
        combo_box.addItems(Window.item_list)

        add_combobox_button = QPushButton("ADD NEW", self)
        add_combobox_button.setGeometry(110, 70, 100, 30)
        add_combobox_button.clicked.connect(self.combobox_adding)

    def combobox_adding(self):
        text, pressed = QInputDialog.getText(self, "New recording", "Name:", QLineEdit.Normal, "")
        if pressed:
            Window.item_list.append(text)

App = QApplication(sys.argv)
window = Window()
sys.exit(App.exec())