default O getOrElse(WithTags input, O defaultValue) {
      List<O> matches = getMatches(input);
      return matches.isEmpty() ? defaultValue : matches.getFirst();
    }
Returns the data value associated with the first expression that match an input element, or {@code defaultValue}
if none match.
planetiler-core/src/main/java/com/onthegomap/planetiler/expression/MultiExpression.java