code: def setUp(self):
      self.rgb_array = np.random.randint(0, 255, (3, 3, 4))
  
imports: import numpy
  from holoviews.element import HSV, RGB, Curve, Image, QuadMesh, Raster
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 1 for calling the TestRGB obj's underlying member method code with example usage: obj.setUp() without return types