How can I make this code work? (lambda) (PyGtk) : So I am trying to work with the lambda function to connect the buttons of my calculator with a funtion. Here is some of my code:

    button1 = Gtk.Button(label = "1")
        lambda event: self.button_clicked(event, "1"), button1
        vbox.pack_start(button1 ,True, True, 0)
        vbox.pack_end(button1,True,True,0)
        self.add(button1)



        def button_clicked(self, value):
        if (value != None):
            if (value != "="):
                # Add something to the text
                self.entry.set_text(self.entry.get_text() + str(value))
            else:
                # Evaluate the text
                self.result = eval(self.entry.get_text())
                self.entry.set_text(self.result)
        else:
            # Clear the text
            self.entry.set_text("")

Am I using the lambda function the right way? And if not how can I change the code. I would appreciate an answer.