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


def my_custom_fn(n):
    print("Button %d was clicked" % n)


class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.setWindowTitle("My Awesome App")

        layout = QVBoxLayout()
        for n in range(10):
            btn = QPushButton(str(n))
            btn.pressed.connect(lambda val=n: my_custom_fn(val))
            layout.addWidget(btn)

        widget = QWidget()
        widget.setLayout(layout)

        self.setCentralWidget(widget)


if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()