code: public Observable<Page<PolicySetDefinitionInner>> listNextAsync(final String nextPageLink) {
          return listNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<PolicySetDefinitionInner>>, Page<PolicySetDefinitionInner>>() {
                  @Override
                  public Page<PolicySetDefinitionInner> call(ServiceResponse<Page<PolicySetDefinitionInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Retrieves the policy set definitions for a subscription.
  This operation retrieves a list of all the policy set definitions in the given subscription.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;PolicySetDefinitionInner&gt; object