code: def test_yaml(precalculated_rf_classifier_explainer):
      yaml = precalculated_rf_classifier_explainer.to_yaml()
      assert isinstance(yaml, str)
  
imports: import pytest
  import pandas
  import numpy
  from pandas.api.types import is_categorical_dtype, is_numeric_dtype
  import plotly.graph_objects
  from explainerdashboard import ClassifierExplainer, ExplainerDashboard
  from explainerdashboard.explainer_methods import IndexNotFoundError
label_desc: Use image node_id 41 for calling a global function with example usage: test_yaml(precalculated_rf_classifier_explainer) without return types