Error generating information using variables with Set

Using the following code

```java
@PactDslBodyBuilder
public class DemoClass {

    private Set<String> aSetString1;

    private Set<Integer> aSetInteger1;

    private Set<Float> aSetFloat1;

    private Set<DemoClass2> aSetClass1;
}
``` 

It gives an error
```
java: java.util.NoSuchElementException: No value present
``` 

Probably missing support for Set Collections