anchor.diff:      lager:info("Adding invariant on node: ~p!", [Node]),
   
       case rpc:call(Node, lasp, enforce_once, [Id, Threshold, EnforceFun]) of
  -        ok ->
  +        {ok, _Pid} ->
               lager:info("Invariant configured!");
           Error ->
               lager:info("Invariant can't be configured: ~p", [Error]),
  
positive.code:     lager:info("Adding invariant on node: ~p!", [Node]),
  
      case rpc:call(Node, lasp, enforce_once, [Id, Threshold, EnforceFun]) of
          ok ->
              lager:info("Invariant configured!");
          Error ->
              lager:info("Invariant can't be configured: ~p", [Error]),
  
negative.code:             lager:info("Adding invariant on node: ~p!", [Node]),
  
              case rpc:call(Node, lasp, enforce_once, [Id, Threshold, EnforceFun]) of
                  {ok, _Pid} ->
                      lager:info("Invariant configured!");
                  Error ->
                      lager:info("Invariant can't be configured: ~p", [Error]),
  