anchor.diff:                     version = 0,
                      aux     = {invalid, merge, stopped},
                      timeout = new_timeout()},
  -    ContentCheck = is_valid_merge_step3(OldEpoch, OldVersion),
  +    ContentCheck = generic_content_check(L1, New, merge_step3),
       DB = get_db_for_id(Id),
       Self = comm:reply_as(self(), 5, {l_on_cseq, merge_reply_step3, L2, ReplyTo, '_'}),
       rbrcseq:qwrite(DB, Self, Id,
  
positive.code:                    version = 0,
                     aux     = empty,
                     timeout = new_timeout()},
      ContentCheck = is_valid_merge_step4(OldEpoch, OldVersion),
      DB = get_db_for_id(Id),
      Self = comm:reply_as(self(), 5, {l_on_cseq, merge_reply_step4, L1, ReplyTo, '_'}),
      rbrcseq:qwrite(DB, Self, Id,
  
negative.code:                     {true, null}
              end
      end.
  
  -spec is_valid_split_step1() ->
      fun ((any(), any(), any()) -> {boolean(), split_step1_failed_reason() | null}). %% content check
  