code: def test_orthogonalize():
      """test that the orthogonalization is OK"""
      X = np.random.randn(100, 5)
      X = _orthogonalize(X)
      K = np.dot(X.T, X)
      K -= np.diag(np.diag(K))
      assert_almost_equal((K**2).sum(), 0, 15)
  
imports: import warnings
  import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_equal
  from ..hemodynamic_models import _hrf_kernel, _orthogonalize, _regressor_names, _resample_regressor, _sample_condition, compute_regressor, glover_hrf, glover_time_derivative, spm_dispersion_derivative, spm_hrf, spm_time_derivative
label_desc: Use image node_id 7 for calling a global function with example usage: test_orthogonalize() without return types