@Override
    public FieldValue createFieldValue() {
        // TODO why do we even need this
        if (delegate == null) {
            delegate = ReferenceDataType.createWithInferredId(docTypeTarget);
        }
        return delegate.createFieldValue();
    }
Model for ReferenceDataType which is more suitable when
we want to end up with NewDocumentType as target type.

@author arnej
config-model/src/main/java/com/yahoo/documentmodel/NewDocumentReferenceDataType.java