code: function(eventTags, logger) {
      if (eventTags && eventTags.hasOwnProperty(REVENUE_EVENT_METRIC_NAME)) {
        var rawValue = eventTags[REVENUE_EVENT_METRIC_NAME];
        var parsedRevenueValue = parseInt(rawValue, 10);
        if (isNaN(parsedRevenueValue)) {
          logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.FAILED_TO_PARSE_REVENUE, MODULE_NAME, rawValue));
          return null;
        }
        logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.PARSED_REVENUE_VALUE, MODULE_NAME, parsedRevenueValue));
        return parsedRevenueValue;
      }
      return null;
    }
docs: Grab the revenue value from the event tags. "revenue" is a reserved keyword.
  @param {Object} eventTags
  @param {Object} logger
  @return {Integer|null}