code: def shade(aggregators, cmap=cmap01):
      """Shade/render the aggregator.
  
      Parameters
      ----------
      aggregators: xarray
        The aggregator(s)  to shade
      cmap: color map
        The colormap to use
  
      Returns
      -------
      img: xarray
        The shaded image.
      """
      img = ds.transfer_functions.shade(aggregators, cmap=cmap)
      img = ds.transfer_functions.set_background(img, "#ffffff")
      return img
  
imports: import os
  import xarray
  import datashader
  import pandas
  import numpy
  import pytest
label_desc: Use image node_id 4 for calling a global function with example usage: shade(aggregators, cmap) and returns: img