code: def get_all_sentinels(env):
      """Get list of all dataset sentinel values in format expected by `XGBClassifier.fit.eval_set`"""
      return [
          (env.train_input, env.train_target),
          (env.validation_input, env.validation_target),
          (env.holdout_input, env.holdout_target),
      ]
  
file_path: hyperparameter_hunter/tests/test_sentinels.py
imports: from hyperparameter_hunter import Environment, CVExperiment, Real, Integer, Categorical, GBRT
  from hyperparameter_hunter import lambda_callback
  from hyperparameter_hunter.sentinels import DatasetSentinel
  from hyperparameter_hunter.settings import G
  from hyperparameter_hunter.utils.learning_utils import get_breast_cancer_data
  import pytest
  import sys
label_desc: Use image node_id 4 for calling a global function with example usage: get_all_sentinels(env) and returns: list