code: def set_rgbmap(self, rgbmap):
          
          self.rgbmap = rgbmap
          t_ = rgbmap.get_settings()
          t_.share_settings(self.t_, keylist=rgbmap.settings_keys)
          rgbmap.add_callback('changed', self.rgbmap_cb)
          self.redraw(whence=2)
docs: Set RGB map object used by this instance.
          It controls how the values in the image are mapped to color.
  
          Parameters
          ----------
          rgbmap : `~ginga.RGBMap.RGBMapper`
              RGB map.