code: def unlink(self, *others):
          
          if not len(others):
              others = self.links[:]
          for p in self.links[:]:
              if p in others:
                  p.teardown()
          return self
docs: Unlink (disassociate) the specified properties object.
          @param others: The list object to unlink.  Unspecified means unlink all.
          @type others: [L{Properties},..]
          @return: self
          @rtype: L{Properties}