code: def test_get_feature_names_out(shape):
      """Check `get_feature_names_out` for `IsotonicRegression`."""
      X = np.arange(10)
      if shape == "2d":
          X = X.reshape(-1, 1)
      y = np.arange(10)
  
      iso = IsotonicRegression().fit(X, y)
      names = iso.get_feature_names_out()
      assert isinstance(names, np.ndarray)
      assert names.dtype == object
      assert_array_equal(["isotonicregression0"], names)
  
imports: import copy
  import pickle
  import warnings
  import numpy
  import pytest
  from scipy.special import expit
  import sklearn
  from sklearn.datasets import make_regression
  from sklearn.isotonic import IsotonicRegression, _make_unique, check_increasing, isotonic_regression
  from sklearn.utils import shuffle
  from sklearn.utils._testing import assert_allclose, assert_array_almost_equal, assert_array_equal
  from sklearn.utils.validation import check_array
label_desc: Use image node_id 39 for calling a global function with example usage: test_get_feature_names_out(shape) without return types