anchor.diff:                {ok, [{filename(), filename(), syntaxTree()}]} |
                 {error, term()}).
   apply_changes(Module, Args, CandsNotToChange) ->
  -    wrangler_gen_refac_server:add_value({self(), {false, CandsNotToChange}}),
  +    wrangler_gen_refac_server:set_flag({self(), {false, CandsNotToChange}}),
       case apply(Module, transform, [Args]) of
           {ok, Res} ->
  -            wrangler_gen_refac_server:delete_value(self()),
  +            wrangler_gen_refac_server:delete_flag(self()),
               refac_write_file:write_refactored_files(
                 Res, 'emacs', Args#args.tabwidth, "");
           {error, Reason} ->
  -            wrangler_gen_refac_server:delete_value(self()),
  +            wrangler_gen_refac_server:delete_flag(self()),
               {error, Reason}
       end.
   
  
positive.code: %% to all refactorings.
  %%  
  %% The user module should export:
  %% ```input_pars() 
  %%      ===> [string()]'''
  %%  `input_pars' returns the list of prompt strings to be used when 
  %%   the refactorer asks the user for input. There should be one 
  %%   prompt string for each input.
  %% ```select_focus(Args::#args{}) 
  
negative.code: %%   `{error, Reason}' if the user didn't select the kind of entity 
  %%   expected; or `{ok, term()' when a valid focus of interest has been
  %%   selected.
  %%  ```check_pre_cond(Args::#args{})
  %%       ===> ok | {error, Reason}'''
  %%   This function checks whether the pre-conditions of the refactoring 
  %%   hold, and returns `ok' if the pre-condition checking passes, otherwise
  