public Arguments subset(String... allowedKeys) {
    Set<String> allowed = new HashSet<>();
    for (String key : allowedKeys) {
      allowed.add(normalize(key));
    }
    return new Arguments(
      key -> allowed.contains(normalize(key)) ? provider.apply(key) : null,
      () -> keys.get().stream().filter(key -> allowed.contains(normalize(key))).toList()
    );
  }
Returns a view of this instance, that only supports requests for {@code allowedKeys}.
planetiler-core/src/main/java/com/onthegomap/planetiler/config/Arguments.java