code: def getAdjacentClone(self, i, south=True):
          
          rr = xrange(i + 1, len(self)) if south else xrange(i - 1, -1, -1)
          a = self[i]
          for ix in rr:
              x = self[ix]
              if x.object != a.object:
                  break
              return x
          return None
docs: Returns adjacent clone name, either the line before or after the current
          line.