docs: public static Object toData(Literal lit) {
      if (lit == null) throw new IllegalArgumentException("Can't convert null literal");
      if (lit instanceof TypedLiteral) return toData((TypedLiteral)lit);
      // Untyped literals are xsd:string
      // Note this isn't strictly correct; language tags will be lost here.
      return lit.getLexical();
    }