code: public static Attribute createFromEncoded(String unencodedKey, String encodedValue) {
          String value = Entities.unescape(encodedValue, true);
          return new Attribute(unencodedKey, value, null); // parent will get set when Put
      }
docs: Create a new Attribute from an unencoded key and a HTML attribute encoded value.
  @param unencodedKey assumes the key is not encoded, as can be only run of simple \w chars.
  @param encodedValue HTML attribute encoded value
  @return attribute