code: def test__gen_two_subplots_with_ax(self):
      fig = plt.gcf()
      gen = _gen_two_subplots(
          f=lambda **kwargs: None, fig=fig, ax="test"
      )
      # On the first yield, no subplot should be added since ax was passed
      next(gen)
      assert fig.get_axes() == []
      # On the second, the one axis should match fig.subplot(2, 1, 2)
      next(gen)
      axes = fig.get_axes()
      assert len(axes) == 1
      subplot_geometry = list(
          axes[0].get_subplotspec().get_geometry()[:-1]
      )
      subplot_geometry[-1] += 1
      assert subplot_geometry == [2, 1, 2]
  
imports: import pytest
  from pandas import DataFrame
  from pandas.tests.plotting.common import _check_plot_works, _check_ticks_props, _gen_two_subplots
label_desc: Use image node_id 2 for calling the TestCommon obj's underlying member method code with example usage: obj.test__gen_two_subplots_with_ax() without return types