import sys

from PyQt6.QtWidgets import QApplication, QWidget, QPushButton, QVBoxLayout


class Window(QWidget):
    def __init__(self) -> None:
        super().__init__()
        self.setGeometry(*(500,) * 4)
        self.setWindowTitle("Окно")

        btn1 = QPushButton("One")
        btn2 = QPushButton("Two")
        btn3 = QPushButton("Three")

        layout = QVBoxLayout()
        layout.addWidget(btn1)
        layout.addWidget(btn2)
        layout.addWidget(btn3)

        self.setLayout(layout)


def main() -> None:
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec())


if __name__ == "__main__":
    main()