anchor.diff:  -export([start_link/0]).
   
   -export([get_user/2]).
  +-export([remove_user_by_pid/1]).
   
   %% gen_server.
   -export([init/1]).
  
positive.code: handle_call({create,User}, _From, State) ->
      Result = create_new_user(User),
      {reply, Result, State};
  handle_call(_Request, _From, State) ->
  	{reply, ignored, State}.
  
  
negative.code: %% set_pid_for_id(ID,Pid) ->
  %%    tts_data:user_update_pid(ID,Pid). 
  
  delete_user_pid(Pid) ->
      tts_data:user_delete_pid(Pid),
      ok.
  