code: def test_early_stopping_skl(self):
      from sklearn.datasets import load_breast_cancer
  
      X, y = load_breast_cancer(return_X_y=True)
      early_stopping_rounds = 5
      cls = xgb.XGBClassifier(
          early_stopping_rounds=early_stopping_rounds,
          eval_metric="error",
      )
      cls.fit(X, y, eval_set=[(X, y)])
      booster = cls.get_booster()
      dump = booster.get_dump(dump_format="json")
      assert (
          len(dump) - booster.best_iteration
          == early_stopping_rounds + 1
      )
  
imports: import json
  import os
  import tempfile
  from typing import Union
  import pytest
  import xgboost
  from xgboost import testing
label_desc: Use image node_id 7 for calling the TestCallbacks obj's underlying member method code with example usage: obj.test_early_stopping_skl() without return types