diff --git a/include/mcc/mcc_keyvalue.h b/include/mcc/mcc_keyvalue.h
index 036ff9a..aa5384c 100644
--- a/include/mcc/mcc_keyvalue.h
+++ b/include/mcc/mcc_keyvalue.h
@@ -411,7 +411,7 @@ public:
 
         std::error_code ec{};
 
-        auto write_rec = [&output_buffer, &rec_delim, &ec, this]<size_t I = 0>(this auto& self) {
+        auto write_rec = [&output_buffer, &rec_delim, &ec, this]<size_t I = 0>(this auto& self) -> void {
             if constexpr (I < NUMBER_OF_RECORDS) {
                 if constexpr (OPOLICY == MccKeyValueHolder::OPOLICY_CHANGED_ONLY) {
                     if (_changedKey.count(_hashes[I]) == 0) {
@@ -425,41 +425,6 @@ public:
                     return;
                 }
 
-                // using val_t = std::remove_cvref_t<decltype(std::get<I>(_keyValue).value)>;
-
-                // auto key = std::get<I>(_keyValue).key;
-
-                // std::string buff;
-                // auto err =
-                //     MccSerializer<val_t>{}(buff, std::get<I>(_keyValue).value, std::get<I>(_keyValue).serial_pars);
-                // if (err) {
-                //     ec = MccKeyValueHolderErrorCode::ERROR_SERIAL;
-                //     return;
-                // } else {
-                //     size_t hash = _hashes[I];
-                //     // write head comment
-                //     if (_headComment[hash].size()) {
-                //         for (auto const& comm : _headComment[hash]) {
-                //             if (comm.has_value()) {
-                //                 std::format_to(std::back_inserter(output_buffer), "{}{}", COMM_SEQ, comm.value());
-                //             }
-                //             std::ranges::copy(rec_delim, std::back_inserter(output_buffer));
-                //         }
-                //     }
-
-                //     // key and value
-                //     std::format_to(std::back_inserter(output_buffer), "{}{}{}", key, KEY_VALUE_DELIM, buff);
-
-                //     // inline comment
-                //     if (_inlineComment[hash].size()) {
-                //         std::format_to(std::back_inserter(output_buffer), " {}{}", COMMENT_SEQ,
-                //         _inlineComment[hash]);
-                //     }
-
-                //     // record delimiter
-                //     std::ranges::copy(rec_delim, std::back_inserter(output_buffer));
-                // }
-
                 self.template operator()<I + 1>();
             }
         };