docstr: test shap_backend
docstr_tok: ["test","shap_backend"]
code: def test_shap_backend_init(self):
      """
      test shap_backend
      """
      for model in self.model_list:
          print(type(model))
          model.fit(self.x_df, self.y_df)
          backend_xpl = ShapBackend(model)
          assert hasattr(backend_xpl, "explainer")
  
file_path: shapash/tests/unit_tests/backend/test_shap_backend.py
imports: import unittest
  import numpy
  import pandas
  import sklearn.ensemble
  import xgboost
  import lightgbm
  import catboost
  from shapash.backend.shap_backend import ShapBackend
label_desc: Use image node_id 2 for calling the TestShapBackend obj's underlying member method code with example usage: obj.test_shap_backend_init() without return types