code: def test_pyramid_reduce_rgb(channel_axis):
      image = data.astronaut()
      rows, cols, dim = image.shape
      image = np.moveaxis(image, source=-1, destination=channel_axis)
      out_ = pyramids.pyramid_reduce(
          image, downscale=2, channel_axis=channel_axis
      )
      out = np.moveaxis(out_, channel_axis, -1)
      assert_array_equal(out.shape, (rows / 2, cols / 2, dim))
  
imports: import math
  import pytest
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_equal, assert_equal
  from skimage import data
  from skimage._shared.utils import _supported_float_type
  from skimage.transform import pyramids
label_desc: Use image node_id 1 for calling a global function with example usage: test_pyramid_reduce_rgb(channel_axis) without return types