code: def test_linreg_random_index(
      precalculated_linear_regression_explainer,
  ):
      assert isinstance(
          precalculated_linear_regression_explainer.random_index(), int
      )
      assert isinstance(
          precalculated_linear_regression_explainer.random_index(
              return_str=True
          ),
          str,
      )
  
imports: import pytest
  import pandas
  import numpy
  import shap
  import plotly.graph_objects
label_desc: Use image node_id 3 for calling a global function with example usage: test_linreg_random_index(precalculated_linear_regression_explainer) without return types