docs: def links(self):
          """Generate the coordinates of all working links.
  
          Yields
          ------
          (x, y, :py:class:`rig.links.Links`)
              A working link leaving a chip from the perspective of the chip. For
              example ``(0, 0, Links.north)`` would be the link going north from
              chip (0, 0) to chip (0, 1).
          """
          for (x, y), chip_info in iteritems(self):
              for link in chip_info.working_links:
                  yield (x, y, link)