code: def objects_reachable_from(obj):
      
      # Depth-first search.
      found = ObjectGraph.vertex_set()
      to_process = [obj]
      while to_process:
          obj = to_process.pop()
          found.add(obj)
          for referent in gc.get_referents(obj):
              if referent not in found:
                  to_process.append(referent)
      return ObjectGraph(found)
docs: Return graph of objects reachable from *obj* via ``gc.get_referrers``.
  
      Returns an :class:`~refcycle.object_graph.ObjectGraph` object holding all
      objects reachable from the given one by following the output of
      ``gc.get_referrers``.  Note that unlike the
      :func:`~refcycle.creators.snapshot` function, the output graph may
      include non-gc-tracked objects.