anchor.diff:      MRef = monitor(process, Session),
       NewSessions = [ {Session, MRef} | lists:keydelete(Session,1,Sessions) ],
       {reply, ok, State#state{sessions=NewSessions}};
  -handle_call({add_token_map,TokenMap}, _From, State) ->
  -    {ok, NewState} = update_token(TokenMap,State),
  +handle_call({add_credential_map,CredentialMap},_From,State) ->
  +    {ok, NewState} = add_credential_to_state(CredentialMap,State),
       {reply, ok, NewState};
   handle_call(_Request, _From, State) ->
   	{reply, ignored, State}.
  
positive.code: -export([get_user_info/1]).
  -export([get_credential_list/1]).
  -export([connect_session/2]).
  -export([add_token/2]).
  -export([shutdown/1]).
  
  
  
negative.code:     %TODO: implement
      false.
  
  add_credential_to_state(#{ token := T } = Cred, State) ->
      %TODO: change for keyfind will perform better
      #state{ token = TokenList, credentials = CredList} = State,
      NewTokenList = [T | TokenList],
      NewCredList = [Cred | CredList],
      NewState = State#state{
                      token = NewTokenList,
                      credentials = NewCredList
                  },
      {ok, NewState}.
  
  remove_session_from_list(MonitorRef,Sessions) ->
      lists:keydelete(MonitorRef,2,Sessions).
  