code: private List<Object> normalizeList(List<Object> list) {
      	List<Object> result = new ArrayList<Object>();
      	for (Object o : list) {
      		if (o == null) {
      			result.add(nullLiteral);
      		} else if (o instanceof Boolean) {
      			result.add(((Boolean) o).toString());
      		} else if (o instanceof List<?>) {
      			result.add(normalizeList((List<Object>) o));
      		} else if (o instanceof Map<?, ?>) {
      			result.add(normalizeMap((Map<String, Object>) o));
      		} else if (!(o instanceof Number)) {
      			result.add(o);
      		}
      	}
      	return result;
      }
docs: Helper for map normalization; inspects list and returns
  a replacement list that has been normalized.
  @param list
  @return Normalized list for encoding/hashing/signing