code: def test_ill_conditioned_2d_channel_activations():
      with pytest.warns(RuntimeWarning):
          C = iem_2d._define_trial_activations(np.ones((nobs, 2)))
          assert np.linalg.matrix_rank(C) == 1
  
imports: import pytest
  import numpy
  import logging
  from brainiak.reconstruct.iem import InvertedEncoding1D, InvertedEncoding2D
  from brainiak.utils.fmrisim import generate_1d_gaussian_rfs, generate_1d_rf_responses
  from scipy.stats import circmean
label_desc: Use image node_id 20 for calling a global function with example usage: test_ill_conditioned_2d_channel_activations() without return types