code: public Observable<Page<StorageAccountItem>> getStorageAccountsNextAsync(final String nextPageLink) {
          return getStorageAccountsNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<StorageAccountItem>>, Page<StorageAccountItem>>() {
                  @Override
                  public Page<StorageAccountItem> call(ServiceResponse<Page<StorageAccountItem>> response) {
                      return response.body();
                  }
              });
      }
docs: List storage accounts managed by the specified key vault. This operation requires the storage/list 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;StorageAccountItem&gt; object