code: def test_must_be_rgb_throws_gray(self):
      x = cellprofiler_core.image.ImageSet(0, {}, {})
      numpy.random.seed(22)
      x.add(
          "image",
          cellprofiler_core.image.Image(
              numpy.random.uniform(size=(10, 20))
          ),
      )
      with pytest.raises(ValueError):
          x.get_image("image", must_be_rgb=True)
  
file_path: CellProfiler/tests/core/image/test_image_set.py
imports: import numpy
  import pytest
  import cellprofiler_core.image
label_desc: Use image node_id 11 for calling the TestImageSet obj's underlying member method code with example usage: obj.test_must_be_rgb_throws_gray() without return types