code: def test_plot_obj(self, model_type):
      pass
  
imports: import pytest
  import joblib
  import os
  import json
  import numpy
  import pandas
  from itertools import product
  import matplotlib
  from abc import ABC, abstractmethod
  import warnings
label_desc: Use image node_id 5 for calling the PlotTestBase obj's underlying member method code with example usage: obj.test_plot_obj(model_type) without return types