code: def _test_plot(self, params):
      # randomly choose a model_type
      model_type = np.random.choice(self.model_types)
      if params.get("which_classes", None) is not None:
          model_type = "multi-class"
  
      for plot_obj in self.get_plot_objs(model_type):
          plot_obj.plot(**params)
          self.close_plt(params)
          break
  
imports: import numpy
  import pytest
  import copy
  from abc import abstractmethod
  from pdpbox.pdp import PDPResult, PDPIsolate, PDPInteract
  from pdpbox.utils import FeatureInfo, _make_list
  from conftest import DummyModel, PlotTestBase
label_desc: Use image node_id 3 for calling the _TestPDPBase obj's underlying member method code with example usage: obj._test_plot(params) without return types