@Nullable
  public static XPathType getDeclaredType(XmlTag element) {
    final XmlAttribute typeAttr = element.getAttribute("as");
    final XPathType returnType;
    if (typeAttr != null) {
      final String value = typeAttr.getValue();
      returnType = value != null ? XPath2Type.fromName(QNameUtil.createQName(value, element)) : null;
      return returnType != null ? returnType : XPathType.UNKNOWN;
    }
    return null;
  }
@Nullable
  public static XPathType getDeclaredType(XmlTag element)