如何将新窗口放置在PyQt5中现有的主窗口位置(而不是屏幕中心)？

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QWidget


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('主窗口')
        self.setGeometry(100, 100, 500, 500)

        self.button = QPushButton('打开新窗口', self)
        self.button.setGeometry(50, 50, 200, 50)
        self.button.clicked.connect(self.open_new_window)

    def open_new_window(self):
        new_window = QWidget()
        new_window.setWindowTitle('新窗口')
        new_window.setGeometry(self.pos().x(), self.pos().y(), 300, 200)
        new_window.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec())