def ttl_from_targz(ttl_filename)
      package_dir = config.fetch('package_dir')
      ttl_path = File.join(source_slug, 'data/obj/root', ttl_filename)
      ROF::Utility.file_from_targz(File.join(package_dir, source_slug + '.tar.gz'), ttl_path)
      fetch_from_ttl(File.join(package_dir, ttl_path))
    end
def ttl_from_targz(ttl_filename)
      package_dir = config.fetch('package_dir')
      ttl_path = File.join(source_slug, 'data/obj/root', ttl_filename)
      ROF::Utility.file_from_targz(File.join(package_dir, source_slug + '.tar.gz'), ttl_path)
      fetch_from_ttl(File.join(package_dir, ttl_path))
    end
extracts given ttl file from JHU tar.gz package
 - assumed to live under data/obj/root
 @return [Array<Hash>] the first element is the "work" and the additional elements, if any, are the contributor(s)