private Object createEmptyObject(Class<?> type) {
    try {
      return type.newInstance();
    } catch (Exception e) {
      return null;
    }
  }
A response strategy that returns zero, an "empty" object, or a "dummy" object,
depending on the method's declared return type.
spock-core/src/main/java/org/spockframework/mock/EmptyOrDummyResponse.java