private Optional<Path> normalizePathInEnv(final String envName) {
        final List<Path> paths = normalizePathsInEnv(envName, false);
        if (paths.size() > 1) {
            throw new IllegalStateException("Multiple paths returned for an unsplit path.");
        }

        if (paths.isEmpty()) {
            return Optional.empty();
        }
        return Optional.of(paths.get(0));
    }
Returns normalized paths in a specified property from the command line.

<p>Note that a path in the command line should be an absolute path, or a relative path from the working directory.
embulk-core/src/main/java/org/embulk/cli/EmbulkSystemPropertiesBuilder.java