code: private void parseParenthesizedExpr() throws TTXPathException {
  
          consume(TokenType.OPEN_BR, true);
          if (!(mToken.getType() == TokenType.CLOSE_BR)) {
              parseExpression();
          }
          consume(TokenType.CLOSE_BR, true);
  
      }
docs: Parses the the rule PatenthesizedExpr according to the following
  production rule:
  <p>
  [45] ParenthesizedExpr ::= "(" Expr? ")" .
  </p>
  
  @throws TTXPathException