code: def _generic_mixer(slice1, slice2, mixer_name, **kwargs):
      
  
      mixer_name = mixer_name.lower()
      if mixer_name in ['color_mix', 'rgb']:
          mixed = _mix_color(slice1, slice2, **kwargs)
          cmap = None  # data is already RGB-ed
      elif mixer_name in ['checkerboard', 'checker', 'cb', 'checker_board']:
          checkers = _get_checkers(slice1.shape, **kwargs)
          mixed = _checker_mixer(slice1, slice2, checkers)
          cmap = 'gray'
      elif mixer_name in ['diff', 'voxelwise_diff', 'vdiff']:
  
          mixed, cmap = _diff_image(slice1, slice2, **kwargs)
          # if kwargs['overlay_image'] is True:
          #     diff_cmap = diff_colormap()
          #     plt.imshow(slice1, alpha=kwargs['overlay_alpha'], **display_params)
          #     plt.hold(True)
          #     plt.imshow(mixed,
          #                cmap=diff_cmap,
          #                vmin=min_value, vmax=max_value,
          #                **display_params)
          # else:
          #     plt.imshow(mixed, cmap=cmap,
          #                vmin=min_value, vmax=max_value,
          #                **display_params)
  
      else:
          raise ValueError('Invalid mixer name chosen.')
  
      disp_params = dict(cmap=cmap)
  
      return mixed, disp_params
docs: Generic mixer to process two slices with appropriate mixer
          and return the composite to be displayed.