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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 register_on_can_show_window(self, callback):
 """Set the callback function to consume on can show window events. This occurs when the console window is to be activated and brought to the foreground of the desktop of the host PC. If this behaviour is not desired a call to event.add_veto will stop this from happening. Callback receives a ICanShowWindowEvent object. Returns the callback_id """

        event_type = library.VBoxEventType.on_can_show_window
        return self.event_source.register_callback(callback, event_type)