code: def test_explain_catboost_regressor(boston_train):
      xs, ys, feature_names = boston_train
      catb = CatBoostRegressor().fit(xs, ys)
      assert _is_regression(catb)
      res = explain_weights(catb)
      for expl in format_as_all(res, catb):
          assert "12" in expl
      res = explain_weights(catb, feature_names=feature_names)
      for expl in format_as_all(res, catb):
          assert "LSTAT" in expl
  
file_path: eli5/tests/test_catboost.py
imports: from __future__ import absolute_import
  import pytest
  from catboost import CatBoostClassifier, CatBoostRegressor, CatBoost, Pool
  import numpy
  from eli5.explain import explain_weights
  from .utils import format_as_all
  from eli5.catboost import _is_regression
label_desc: Use image node_id 2 for calling a global function with example usage: test_explain_catboost_regressor(boston_train) without return types