labelIndex,
          )
        if (rule != null) {
          exception = rule
          break
        }
      }
    }

    if (exception != null) {
      // Signal we've identified an exception rule.
      exception = "!$exception"
      return exception.split('.')
    } else if (exactMatch == null && wildcardMatch == null) {
      return PREVAILING_RULE
    }