def on_stage_setup(self):
        """ This method gets called when the pipeline setups the render
        stages. You should create your custom stages here """

        # Setup a demo stage
        self.stage = self.create_stage(DemoStage)
 This method gets called when the pipeline setups the render
        stages. You should create your custom stages here 
metadrive/render_pipeline/rpplugins/plugin_prefab/plugin.py