code: def test_label_outer_span():
      fig = plt.figure()
      gs = fig.add_gridspec(3, 3)
      # +---+---+---+
      # |   1   |   |
      # +---+---+---+
      # |   |   | 3 |
      # + 2 +---+---+
      # |   | 4 |   |
      # +---+---+---+
      a1 = fig.add_subplot(gs[0, 0:2])
      a2 = fig.add_subplot(gs[1:3, 0])
      a3 = fig.add_subplot(gs[1, 2])
      a4 = fig.add_subplot(gs[2, 1])
      for ax in fig.axes:
          ax.label_outer()
      check_ticklabel_visible(
          fig.axes,
          [False, True, False, True],
          [True, True, False, False],
      )
  
imports: import itertools
  import numpy
  import pytest
  from matplotlib.axes import Axes, SubplotBase
  import matplotlib.pyplot
  from matplotlib.testing.decorators import check_figures_equal, image_comparison
label_desc: Use image node_id 6 for calling a global function with example usage: test_label_outer_span() without return types