How to access QstatusBar in QMainWindows from a widget class?

I'm trying to change the text of a Qstatusbar created in a mainwindows Class from another class

I've try several thing for the web but didn't find the answer ...

class MainWindow(QMainWindow):

    def __init__(self, widget):
        QMainWindow.__init__(self)
        self.setWindowTitle("Main Windows")

        # Status Bar
        self.main_statusbar = QStatusBar()
        self.main_statusbar.showMessage("Ready")
        self.setStatusBar(self.main_statusbar)

class Widget(QWidget):

    def __init__(self):
        QWidget.__init__(self)
        self.buttons_layout = QHBoxLayout()
        self.btn_enregister = QPushButton("Save")
        self.btn_enregister.clicked.connect(self.save_information)

    def save_information(self):

        if self.line_prenom.text() and self.line_nom.text():
            info_client.write(db)
        else:
            (this line)---> main_statusbar.showMessage("Fidouda")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    widget = Widget()
    window = MainWindow(widget)
    window.resize(800, 700)
    window.show()
    sys.exit(app.exec_())

I would like to be able to modify the statusbar text created in the MainWindow class from the Widget class

One of the advantages of Qt over other libraries are the signals that allow you to notify between objects, in this case it is the best option:

from PySide2.QtCore import Signal # <---


class MainWindow(QMainWindow):

    def __init__(self, widget):
        QMainWindow.__init__(self)
        self.setWindowTitle("Main Windows")

        # Status Bar
        self.main_statusbar = QStatusBar()
        self.main_statusbar.showMessage("Ready")
        self.setStatusBar(self.main_statusbar)
        widget.messageChanged.connect(self.main_statusbar.showMessage) # <---

class Widget(QWidget):
    messageChanged = Signal(str) # <---

    # ...

    def save_information(self):

        if self.line_prenom.text() and self.line_nom.text():
            info_client.write(db)
        else:
            self.messageChanged.emit("Fidouda") # <---