docs: public static <T> Optional<Map<T, NullableValue>> extractFixedValues(TupleDomain<T> tupleDomain)
      {
          if (!tupleDomain.getDomains().isPresent()) {
              return Optional.empty();
          }
  
          return Optional.of(tupleDomain.getDomains().get()
                  .entrySet().stream()
                  .filter(entry -> entry.getValue().isNullableSingleValue())
                  .collect(toLinkedMap(Map.Entry::getKey, entry -> new NullableValue(entry.getValue().getType(), entry.getValue().getNullableSingleValue()))));
      }