anchor.diff:  
   -export_type([riak_client/0]).
   
  -%% @spec new(Node, ClientId) -> riak_client().
  +%% @spec new(Node, ClientId) -> riak_client()
   %% @doc Return a riak client instance.
   new(Node, ClientId) ->
       {?MODULE, [Node,ClientId]}.
  
positive.code: %%       {error, notfound} |
  %%       {error, timeout} |
  %%       {error, {n_val_violation, N::integer()}} |
  %%       {error, Err :: term()}
  %%       {error, Err :: term(), details()}
  %% @doc Store RObj in the cluster.
  put(RObj, Options, {?MODULE, [Node, _ClientId]}=THIS) when is_list(Options) ->
  
negative.code: filter_keys(Bucket, Fun, {?MODULE, [_Node, _ClientId]}=THIS) ->
      list_keys(Bucket, Fun, ?DEFAULT_TIMEOUT, THIS).
  
  %% @spec filter_keys(riak_object:bucket(), Fun :: function(), TimeoutMillisecs :: integer(),
  %%                   riak_client()) ->
  %%       {ok, [Key :: riak_object:key()]} |
  %%       {error, timeout} |
  