code: def test_shade_mpl_cmap(agg):
      cm = pytest.importorskip("matplotlib.cm")
      img = tf.shade(agg.a, how="log", cmap=cm.viridis)
      sol = np.array(
          [
              [0, 4283695428, 4287524142],
              [4287143710, 0, 4282832267],
              [4280213706, 4280608765, 0],
          ]
      )
      sol = tf.Image(sol, coords=coords, dims=dims)
      assert_eq_xr(img, sol)
  
imports: from __future__ import annotations
  from io import BytesIO
  import numpy
  import xarray
  import dask.array
  import PIL
  import pytest
  import datashader.transfer_functions
  from datashader.tests.test_pandas import assert_eq_ndarray, assert_eq_xr, assert_image_close
label_desc: Use image node_id 13 for calling a global function with example usage: test_shade_mpl_cmap(agg) without return types