code: def test_plot_waveforms(display):
      """Test plot_waveforms"""
      n_matrices, n_channels, n_times = 16, 3, 50
      X = np.random.randn(n_matrices, n_channels, n_times)
      plot_waveforms(X, display)
      plot_waveforms(X, display, times=np.arange(n_times))
  
      X = np.random.randn(n_matrices, 1, n_times)
      plot_waveforms(X, display)
  
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 4 for calling a global function with example usage: test_plot_waveforms(display) without return types