code: def test_plot_calibration(fname, axes):
      """Test plotting calibration data."""
      import matplotlib.pyplot as plt
  
      # Set the non-interactive backend
      plt.switch_backend("agg")
  
      if axes:
          axes = plt.subplot()
      calibrations = read_eyelink_calibration(fname)
      cal_left = calibrations[0]
      fig = cal_left.plot(show=True, show_offsets=True, axes=axes)
      ax = fig.axes[0]
  
      scatter1 = ax.collections[0]
      scatter2 = ax.collections[1]
      px, py = cal_left["positions"].T
      gaze_x, gaze_y = cal_left["gaze"].T
  
      assert (
          ax.title.get_text() == f"Calibration ({cal_left['eye']} eye)"
      )
      assert len(ax.collections) == 2  # Two scatter plots
  
      np.testing.assert_allclose(
          scatter1.get_offsets(), np.column_stack((px, py))
      )
      np.testing.assert_allclose(
          scatter2.get_offsets(), np.column_stack((gaze_x, gaze_y))
      )
      plt.close(fig)
  
imports: import numpy
  import pytest
  from mne.datasets.testing import data_path, requires_testing_data
  from ..calibration import Calibration, read_eyelink_calibration
label_desc: Use image node_id 3 for calling a global function with example usage: test_plot_calibration(fname, axes) without return types