code: def test_with_3d_input_array(self):
      # (H, W, 1)
      heatmaps_arr = self.heatmaps_arr
      expected = self.expected_arr
      heatmaps = ia.HeatmapsOnImage(
          heatmaps_arr[..., np.newaxis],
          shape=(2, 3),
          min_value=-2.0,
          max_value=10.0,
      )
      assert np.allclose(
          heatmaps.get_arr(), heatmaps_arr[..., np.newaxis]
      )
      assert np.allclose(
          heatmaps.invert().get_arr(), expected[..., np.newaxis]
      )
  
imports: from __future__ import print_function, division, absolute_import
  import sys
  import numpy
  import six.moves
  import imgaug
label_desc: Use image node_id 4 for calling the TestHeatmapsOnImage_invert obj's underlying member method code with example usage: obj.test_with_3d_input_array() without return types