anchor.diff:      forms_expression(Exp).
   
   
  +
   %% @private
   is_21() ->
       erlang:system_info(otp_release) >= "21".
  +
  +
  +%% @private
  +is_21_2() ->
  +    % Erlang 21.0: 10.0.8
  +    % Erlang 21.1: 10.1.8
  +    % Erlang 21.2: 10.2.1
  +    is_21() andalso erlang:system_info(version) >= "10.2.1".
   
   
   %% @private
  
positive.code: 
  %% @private
  make_put_fun() ->
      Exp = case is_21() of
          true ->
              "
                  do_config_put(Key, Value) ->
  
negative.code: 
  %% @private
  make_get_fun() ->
      Exp = case is_21_2() of
          true ->
              "
                  do_config_get(Key) ->
  