anchor.diff:  %% Same as get_apl, but returns only the primaries.
   -spec get_primary_apl(binary(), n_val(), ring(), [node()]) -> preflist2().
   get_primary_apl(DocIdx, N, Ring, UpNodes) ->
  -    UpNodes1 = ordsets:from_list(UpNodes),
  +    UpNodes1 = UpNodes,
       Preflist = riak_core_ring:preflist(DocIdx, Ring),
       {Primaries, _} = lists:split(N, Preflist),
       {Up, _} = check_up(Primaries, UpNodes1, [], []),
  
positive.code: %% Same as get_apl, but returns only the primaries.
  -spec get_primary_apl_chbin(binary(), n_val(), chashbin(), [node()]) -> preflist2().
  get_primary_apl_chbin(DocIdx, N, CHBin, UpNodes) ->
      UpNodes1 = ordsets:from_list(UpNodes),
      Itr = chashbin:iterator(DocIdx, CHBin),
      {Primaries, _} = chashbin:itr_pop(N, Itr),
      {Up, _} = check_up(Primaries, UpNodes1, [], []),
  
negative.code: 
  %% Return true if a node is up
  is_up(Node, UpNodes) ->
      lists:member(Node, UpNodes).
  
  -ifdef(TEST).
  
  