code: def test_geometric_mean_error_non_square_matrix():
      n_features = 5
      mat1 = np.ones((n_features, n_features + 1))
  
      with pytest.raises(ValueError, match="Expected a square matrix"):
          _geometric_mean([mat1])
  
imports: import copy
  import warnings
  from math import cosh, exp, log, sinh, sqrt
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from pandas import DataFrame
  from scipy import linalg
  from sklearn.covariance import EmpiricalCovariance, LedoitWolf
  from nilearn._utils.extmath import is_spd
  from nilearn.connectome.connectivity_matrices import ConnectivityMeasure, _check_spd, _check_square, _form_symmetric, _geometric_mean, _map_eigenvalues, prec_to_partial, sym_matrix_to_vec, vec_to_sym_matrix
  from nilearn.tests.test_signal import generate_signals
label_desc: Use image node_id 20 for calling a global function with example usage: test_geometric_mean_error_non_square_matrix() without return types