code: @Override
      public CloseableValue<String> asString() {
          final Class<?> callerClass = ReflectionHelper.getDirectCallerClass();
          return bindSingeValue(String.class, callerClass);
      }
docs: Evaluates the XPath as a String value. This method is just a shortcut for as(String.class);
  
  @return String value of evaluation result.