code: @Override
      public Object unmarshall(Type feelType, String value) {
          return feel.evaluate( value );
      }
docs: Unmarshalls the string into a FEEL value by executing it.
  
  @param feelType this parameter is ignored by this marshaller and can be set to null
  @param value the FEEL code to execute for unmarshalling
  
  @return the value resulting from executing the code