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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 add_ui(self, klass, *args, **kwargs):
        '''Add an UI element for the current scene. The approach is
        the same as renderers.

        .. warning:: The UI api is not yet finalized

        '''
        ui = klass(self.widget, *args, **kwargs)
        self.widget.uis.append(ui)
        return ui