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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 _load_screen_settings(self):
 """Load screen settings"""

        # display number / use primary display
        combo = self.get_widget('display_n')
        dest_screen = self.settings.general.get_int('display-n')
        # If Guake is configured to use a screen that is not currently attached,
        # default to 'primary display' option.
        screen = self.get_widget('config-window').get_screen()
        n_screens = screen.get_n_monitors()
        if dest_screen > n_screens - 1:
            self.settings.general.set_boolean('mouse-display', False)
            dest_screen = screen.get_primary_monitor()
            self.settings.general.set_int('display-n', dest_screen)

        if dest_screen == ALWAYS_ON_PRIMARY:
            first_item = combo.get_model().get_iter_first()
            combo.set_active_iter(first_item)
        else:
            seen_first = False  # first item "always on primary" is special
            for i in combo.get_model():
                if seen_first:
                    i_int = int(i[0].split()[0])  # extracts 1 from '1' or from '1 (primary)'
                    if i_int == dest_screen:
                        combo.set_active_iter(i.iter)
                else:
                    seen_first = True