code: @Override
      public void _openSubclause() {
          _currentClauseDepth++;
  
          List<QueryToken> tokens = getCurrentWhereTokens();
          appendOperatorIfNeeded(tokens);
          negateIfNeeded(tokens, null);
  
          tokens.add(OpenSubclauseToken.INSTANCE);
      }
docs: Simplified method for opening a new clause within the query