code: public Observable<Page<SasDefinitionItem>> getSasDefinitionsNextAsync(final String nextPageLink) {
          return getSasDefinitionsNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<SasDefinitionItem>>, Page<SasDefinitionItem>>() {
                  @Override
                  public Page<SasDefinitionItem> call(ServiceResponse<Page<SasDefinitionItem>> response) {
                      return response.body();
                  }
              });
      }
docs: List storage SAS definitions for the given storage account. This operation requires the storage/listsas permission.
  
  @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;SasDefinitionItem&gt; object