anchor.diff:  
               case MatchingNodes of
                   [] ->
  +                    lager:debug("Node getting error (NodeId=~p): no such node"),
                       {error, {no_such_node, [{<<"id">>, BinNodeId}]}};
                   [Node] ->
                       Node;
                   _ when is_list(MatchingNodes) ->
                       % This can happen only if the cloud provider is buggy,
                       % that's why it is not reported in the type spec.
  +                    lager:debug("Node getting error (NodeId=~p): multiple "
  +                                "nodes"),
                       {error, {multiple_nodes, [{<<"id">>, BinNodeId}]}}
               end;
           {error, Error} ->
  +            % debug log printed by list_nodes call
               {error, Error}
       end.
   
  
positive.code:         {ok, JsonRes} ->
              {ok, JsonRes};
          {error, Error} ->
              {error, Error}
      end.
  
  
negative.code:         {ok, JsonRes} ->
              {ok, JsonRes};
          {error, Error} ->
              lager:debug("Get key pair error: ~p", [Error]),
              {error, Error}
      end.
  
  