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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_dm(self, num):
 """ Make GUI changes based on data model num. Get info from WD in appropriate format. """

        #enable or disable self.btn1a
        if self.data_model_num == 3:
            self.btn1a.Enable()
        else:
            self.btn1a.Disable()
        #
        # set pmag_gui_dialogs
        global pmag_gui_dialogs
        if self.data_model_num == 2:
            pmag_gui_dialogs = pgd2
            wx.CallAfter(self.get_wd_data2)
        elif self.data_model_num == 3:
            pmag_gui_dialogs = pgd3
            wx.CallAfter(self.get_wd_data)

        # do / re-do menubar
        menubar = pmag_gui_menu.MagICMenu(self, data_model_num=self.data_model_num)
        self.SetMenuBar(menubar)
        self.menubar = menubar