code: public Observable<List<PersonGroup>> listAsync(ListPersonGroupsOptionalParameter listOptionalParameter) {
          return listWithServiceResponseAsync(listOptionalParameter).map(new Func1<ServiceResponse<List<PersonGroup>>, List<PersonGroup>>() {
              @Override
              public List<PersonGroup> call(ServiceResponse<List<PersonGroup>> response) {
                  return response.body();
              }
          });
      }
docs: List person groups and their information.
  
  @param listOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;PersonGroup&gt; object