code: public static ParsedScheduleExpression parse(ScheduleExpression expr)
      {
          ParsedScheduleExpression parsedExpr = new ParsedScheduleExpression(expr);
          parse(parsedExpr);
          return parsedExpr;
      }
docs: Parses the specified schedule expression and returns the result.
  
  @param expr the expression to parse
  @return the parsed schedule expression
  @throws ScheduleExpressionParserException if the expression contains an
  invalid attribute value