anchor.diff:  %% Checks if singleton module can be started.
   %% @end
   %%--------------------------------------------------------------------
  --spec register_singleton_module(Module :: atom(), Node :: node(), State :: #state{}) ->
  -    {ok | already_started, #state{}}.
  +-spec register_singleton_module(Module :: atom(), Node :: node(), State :: state()) ->
  +    {ok | already_started, state()}.
   register_singleton_module(Module, Node, #state{singleton_modules = Singletons} = State) ->
       UsedNode = proplists:get_value(Module, Singletons),
       case UsedNode of
  
positive.code: %% Handling cast messages
  %% @end
  %%--------------------------------------------------------------------
  -spec handle_cast(Request :: term(), State :: term()) -> Result when
      Result :: {noreply, NewState}
      | {noreply, NewState, Timeout}
      | {noreply, NewState, hibernate}
      | {stop, Reason :: term(), NewState},
      NewState :: term(),
      Timeout :: non_neg_integer() | infinity.
  handle_cast({cm_conn_req, Node}, State) ->
      NewState = cm_conn_req(State, Node),
  
negative.code:     | {ok, State, hibernate}
      | {stop, Reason :: term()}
      | ignore,
      State :: state(),
      Timeout :: non_neg_integer() | infinity.
  init(_) ->
      process_flag(trap_exit, true),
  