docs: public static String sqltimestampadd(List<?> parsedArgs) throws SQLException {
      if (parsedArgs.size() != 3) {
        throw new PSQLException(
            GT.tr("{0} function takes three and only three arguments.", "timestampadd"),
            PSQLState.SYNTAX_ERROR);
      }
      String interval = EscapedFunctions.constantToInterval(parsedArgs.get(0).toString(),
          parsedArgs.get(1).toString());
      StringBuilder buf = new StringBuilder();
      buf.append("(").append(interval).append("+");
      buf.append(parsedArgs.get(2)).append(")");
      return buf.toString();
    }