anchor.diff:  -spec get_node(term()) -> node().
   get_node(Label) ->
       {ok, CHash} = application:get_env(ctool, chash),
  -    case is_atom(CHash) of
  +    case ?IS_SINGLE_NODE_CHASH(CHash) of
           true -> CHash;
           _ ->
               Index = chash:key_of(Label),
  
positive.code: %%--------------------------------------------------------------------
  -spec init([node()]) -> ok.
  init([Node]) ->
      application:set_env(ctool, chash, Node);
  init(Nodes) ->
      case application:get_env(ctool, chash) of
          undefined ->
  
negative.code: -export([init/1, cleanup/0, get_chash_ring/0, set_chash_ring/1, get_node/1,
      get_all_nodes/0]).
  
  -define(SINGLE_NODE_CHASH(Node), Node).
  -define(IS_SINGLE_NODE_CHASH(CHash), is_atom(CHash)).
  
  %%%===================================================================
  %%% API
  %%%===================================================================
  