docs: String getNamespaceAliasForUriErrorOnUnknown(String namespaceUri) {
      String result = getAliasForUri(namespaceUri);
      Preconditions.checkArgument(
          result != null,
          "invalid XML: no alias declared for namesapce <%s>; "
              + "work-around by setting XML namepace directly by calling the set method of %s",
          namespaceUri,
          XmlNamespaceDictionary.class.getName());
      return result;
    }