docs: public <T> ImmutableSet<T> objectsFromNamespaces(String baseNamespace,
        String activeNamespacesFeature,
        NamespaceToObjectMapper<? extends T> nameSpaceToObjectMapper) {
      final Parameters subNamespace = copyNamespace(baseNamespace);
      final ImmutableSet.Builder<T> ret = ImmutableSet.builder();
      for (final String activeNamespace : subNamespace.getStringList(activeNamespacesFeature)) {
        if (subNamespace.isNamespacePresent(activeNamespace)) {
          ret.add(nameSpaceToObjectMapper.fromNameSpace(subNamespace.copyNamespace(activeNamespace)));
        } else {
          throw new ParameterException("Expected namespace " + baseNamespace + DELIM + activeNamespace
              + "to exist because of value of " + activeNamespacesFeature + " but "
              + "it did not");
        }
      }
      return ret.build();
    }