code: def validate_cmaps(cmaps):
      
      cmaps = {validate_str(key): validate_colorlist(val) for key, val in cmaps}
      for key, val in six.iteritems(cmaps):
          cmaps.setdefault(key + '_r', val[::-1])
      return cmaps
docs: Validate a dictionary of color lists
  
      Parameters
      ----------
      cmaps: dict
          a mapping from a colormap name to a list of colors
  
      Raises
      ------
      ValueError
          If one of the values in `cmaps` is not a color list
  
      Notes
      -----
      For all items (listname, list) in `cmaps`, the reversed list is
      automatically inserted with the ``listname + '_r'`` key.