PyQt6 Не создаётся ScrollBar в QScrollArea

import sys
 
from PyQt6.QtCore import QSize
from PyQt6.QtWidgets import QApplication, QMainWindow, QPushButton, QWidget, QScrollArea, QLabel
 
 
class Window_303(QWidget):
    def __init__(self):
        super().__init__()
        self.setFixedSize(QSize(500, 500))
        scroll_area = QScrollArea(self)
        dict_303 = {}
        for i in range(0, 50):
            dict_303[f'label_number_{i}'] = QLabel(f'Номер {i}', scroll_area)
            dict_303[f'label_number_{i}'].move(0, 0 + 16 * i)
            dict_303[f'label_number_{i}'].show()
        scroll_area.show()
 
 
class Window(QMainWindow):
    def __init__(self):
        super().__init__()
        self.w = Window_303()
        button = QPushButton("Открыть окно", self)
        button.show()
        button.clicked.connect(self.show_window_303)
        self.show()
 
    def show_window_303(self, checked):
        self.w.show()
 
 
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_window = Window()
    try:
        sys.exit(app.exec())
    except:
        print("Exiting")

class Window_303(QWidget):
    def __init__(self, parent=None):
        super(Window_303, self).__init__(parent)
 
        self.setFixedSize(600, 600)
        scroll_area = QScrollArea(self)
        scroll_area.setGeometry(0, 0, 420, 180)
        scroll_area.setWidgetResizable(False)
 
        container = QWidget()
        scroll_area.setWidget(container)
        dict_303 = {}
        geometry = QRect(10, 10, 0, 0)
        for i in range(0, 50):
            dict_303[f'label_number_{i}'] = QLabel(f'Номер {i}', container)
            dict_303[f'label_number_{i}'].adjustSize()
            dict_303[f'label_number_{i}'].move(geometry.bottomLeft())
            geometry |= dict_303[f'label_number_{i}'].geometry()
 
        geometry.setTopLeft(QPoint(0, 0))
        container.resize(geometry.size())