code: def test_plot(self):
      case1 = self.exp.model_diagnostics(variables=["fare", "embarked"])
      case2 = self.exp.model_diagnostics()
      case3 = self.exp2.model_diagnostics()
  
      self.assertIsInstance(
          case1, dx.model_explanations.ResidualDiagnostics
      )
      self.assertIsInstance(
          case2, dx.model_explanations.ResidualDiagnostics
      )
      self.assertIsInstance(
          case3, dx.model_explanations.ResidualDiagnostics
      )
  
      fig1 = case1.plot(
          title="test1", variable="fare", N=1000, show=False
      )
      fig2 = case2.plot(
          case3,
          variable="sibsp",
          yvariable="abs_residuals",
          N=None,
          show=False,
      )
      fig3 = case2.plot(
          smooth=False,
          line_width=6,
          marker_size=1,
          variable="age",
          show=False,
      )
  
      self.assertIsInstance(fig1, Figure)
      self.assertIsInstance(fig2, Figure)
      self.assertIsInstance(fig3, Figure)
  
file_path: DALEX/python/dalex/test/test_model_diagnostics.py
imports: import unittest
  import numpy
  import pandas
  from sklearn.compose import ColumnTransformer
  from sklearn.impute import SimpleImputer
  from sklearn.neural_network import MLPClassifier
  from sklearn.pipeline import Pipeline
  from sklearn.preprocessing import StandardScaler, LabelEncoder, OneHotEncoder
  import dalex
  from plotly.graph_objs import Figure
  import time
label_desc: Use image node_id 3 for calling the ModelDiagnosticsTestTitanic obj's underlying member method code with example usage: obj.test_plot() without return types