code: def test_igts_identity():
      """Test identity segmentation."""
      X = np.random.random(12).reshape(4, 3)
      id_change_points = IGTS().identity(X)
      assert id_change_points == [0, 4]
  
file_path: sktime/sktime/annotation/tests/test_igts.py
imports: import numpy
  import pytest
  from sktime.annotation.igts import IGTS, InformationGainSegmentation, entropy
label_desc: Use image node_id 3 for calling a global function with example usage: test_igts_identity() without return types