public Path file(String key, String description, Path defaultValue) {
    String value = getArg(key);
    Path file = value == null ? defaultValue : Path.of(value);
    logArgValue(key, description, file);
    return file;
  }
Returns a {@link Path} parsed from {@code key} argument, or fall back to a default if the argument is not set.
planetiler-core/src/main/java/com/onthegomap/planetiler/config/Arguments.java