code: public List<byte[]> getSubAuthorities() {
          final List<byte[]> res = new ArrayList<>(getSubAuthorityCount());
          for (byte[] sub : subAuthorities) {
              if (sub != null) {
                  res.add(Arrays.copyOf(sub, sub.length));
              }
          }
          return Collections.unmodifiableList(res);
      }
docs: Gets sub-authorities: a list of unsigned 32-bit integers that uniquely identifies a principal
  relative to the IdentifierAuthority.
  
  @return sub-authorities.