code: def test_xgbreg_shap_base_value(
      precalculated_xgb_regression_explainer,
  ):
      assert isinstance(
          precalculated_xgb_regression_explainer.shap_base_value(),
          (np.floating, float),
      )
  
imports: import pandas
  import numpy
label_desc: Use image node_id 3 for calling a global function with example usage: test_xgbreg_shap_base_value(precalculated_xgb_regression_explainer) without return types