code: def test_cospectra():
      """Test plot_cospectra"""
      n_freqs, n_channels = 16, 3
      cosp = np.random.randn(n_freqs, n_channels, n_channels)
      freqs = np.random.randn(n_freqs)
      plot_cospectra(cosp, freqs)
  
file_path: pyRiemann/tests/test_utils_viz.py
imports: from conftest import requires_matplotlib
  import numpy
  import pytest
  from pyriemann.utils.viz import plot_embedding, plot_cospectra, plot_waveforms
label_desc: Use image node_id 3 for calling a global function with example usage: test_cospectra() without return types