code: def test_get_synthetic_preds_holdout():
      preds_train, preds_valid = get_synthetic_preds_holdout(
          synthetic_data_func=simulate_nuisance_and_easy_treatment,
          n=1000,
          estimators={
              "S Learner (LR)": LRSRegressor(),
              "T Learner (XGB)": XGBTRegressor(),
          },
      )
  
      assert (
          preds_train["S Learner (LR)"].shape[0]
          == preds_train["T Learner (XGB)"].shape[0]
      )
      assert (
          preds_valid["S Learner (LR)"].shape[0]
          == preds_valid["T Learner (XGB)"].shape[0]
      )
  
file_path: causalml/tests/test_datasets.py
imports: import pytest
  from causalml.dataset import simulate_nuisance_and_easy_treatment, simulate_hidden_confounder, simulate_randomized_trial
  from causalml.dataset import get_synthetic_preds, get_synthetic_summary, get_synthetic_auuc
  from causalml.dataset import get_synthetic_preds_holdout, get_synthetic_summary_holdout
  from causalml.inference.meta import LRSRegressor, XGBTRegressor
label_desc: Use image node_id 3 for calling a global function with example usage: test_get_synthetic_preds_holdout() without return types