code: def unwatch(value):
      
      if not isinstance(value, Watchable):
          raise TypeError("Expected a Watchable, not %r." % value)
      spectator = watcher(value)
      try:
          del value._instance_spectator
      except Exception:
          pass
      return spectator
docs: Return the :class:`Specatator` of a :class:`Watchable` instance.