code: def test_predefinedholdoutsplit_default_iter():
      h_iter = PredefinedHoldoutSplit(valid_indices=[0, 1, 99])
  
      cnt = 0
      for train_ind, valid_ind in h_iter.split(X, y):
          cnt += 1
  
      assert cnt == 1
  
      expect_train_ind = np.array(
          [
              2,
              3,
              4,
              5,
              6,
              7,
              8,
              9,
              10,
              11,
              12,
              13,
              14,
              15,
              16,
              17,
              18,
              19,
              20,
              21,
              22,
              23,
              24,
              25,
              26,
              27,
              28,
              29,
              30,
              31,
              32,
              33,
              34,
              35,
              36,
              37,
              38,
              39,
              40,
              41,
              42,
              43,
              44,
              45,
              46,
              47,
              48,
              49,
              50,
              51,
              52,
              53,
              54,
              55,
              56,
              57,
              58,
              59,
              60,
              61,
              62,
              63,
              64,
              65,
              66,
              67,
              68,
              69,
              70,
              71,
              72,
              73,
              74,
              75,
              76,
              77,
              78,
              79,
              80,
              81,
              82,
              83,
              84,
              85,
              86,
              87,
              88,
              89,
              90,
              91,
              92,
              93,
              94,
              95,
              96,
              97,
              98,
              100,
              101,
              102,
              103,
              104,
              105,
              106,
              107,
              108,
              109,
              110,
              111,
              112,
              113,
              114,
              115,
              116,
              117,
              118,
              119,
              120,
              121,
              122,
              123,
              124,
              125,
              126,
              127,
              128,
              129,
              130,
              131,
              132,
              133,
              134,
              135,
              136,
              137,
              138,
              139,
              140,
              141,
              142,
              143,
              144,
              145,
              146,
              147,
              148,
              149,
          ]
      )
      expect_valid_ind = np.array([0, 1, 99])
      np.testing.assert_equal(train_ind, expect_train_ind)
      assert (valid_ind == expect_valid_ind).all()
  
file_path: mlxtend/mlxtend/evaluate/tests/test_holdout.py
imports: import numpy
  from packaging.version import Version
  from sklearn import __version__
  from sklearn.model_selection import GridSearchCV
  from sklearn.neighbors import KNeighborsClassifier
  from mlxtend.data import iris_data
  from mlxtend.evaluate import PredefinedHoldoutSplit, RandomHoldoutSplit
  from mlxtend.feature_selection import SequentialFeatureSelector
label_desc: Use image node_id 4 for calling a global function with example usage: test_predefinedholdoutsplit_default_iter() without return types