code: def test_num_axes_hist(image_array_2bands, basic_image):
      """We expect one AxesSubplot object per band."""
      f_1, ax_1 = ep.hist(basic_image)
      assert len(f_1.axes) == 1
      f_2, ax_2 = ep.hist(image_array_2bands)
      assert len(f_2.axes) == 2
      plt.close(f_1)
      plt.close(f_2)
  
imports: import numpy
  import pytest
  import matplotlib.pyplot
  import earthpy.plot
label_desc: Use image node_id 2 for calling a global function with example usage: test_num_axes_hist(image_array_2bands, basic_image) without return types