code: public static Pair<String, String> decodeDelegationKey(String encodedValue) {
  		List<String> split = Strings.split(encodedValue, DEFAULT_SEVERITY_SEPARATOR);
  		if (split.size() == 2) {
  			return Tuples.create(split.get(0), split.get(1));
  		} else if (split.size() == 1) {
  			return Tuples.create(split.get(0), SeverityConverter.SEVERITY_WARNING);
  		} else {
  			return null;
  		}
  	}
docs: Returns decoded delegation key or <code>null</code> if encodedValue can not be parsed.
  @return {@link Pair} where getFirst() is delegationKey and getSecond() is the defaultSeverity.
  @see XbaseSeverityConverter#encodeDefaultSeverity(String, String)