code: def test_actual_results_lower_bound_yi(X_train, X_test, arr_desired):
      """Test that the actual results are the expected ones."""
      arr_actual = lower_bound_yi(X_train, X_test)
      np.testing.assert_allclose(
          arr_actual, arr_desired, atol=1e-5, rtol=0
      )
  
imports: import numpy
  import pytest
  import re
  from math import sqrt
  from pyts.metrics.lower_bounds import _lower_bound_yi_x_y, _lower_bound_yi_X_Y, _warping_envelope, _clip
  from pyts.metrics import lower_bound_improved, lower_bound_keogh, lower_bound_kim, lower_bound_yi
  from pyts.metrics import dtw, sakoe_chiba_band
  from pyts.metrics.dtw import _dtw_sakoechiba
  from sklearn.metrics import pairwise_distances
label_desc: Use image node_id 4 for calling a global function with example usage: test_actual_results_lower_bound_yi(X_train, X_test, arr_desired) without return types