 problem about visualize results

Hello! 

 When I  run the code in tutorial: _4. Visualize the result,_ , it has a problem: _could not find function "init_obj"_ and _Error in plot_net(obj4, mode = "heatmap", cell_type = "sensitive") :  unused argument (cell_type = "sensitive")_, could you please tell me how to solve this issue?

Thanks.