code: public Observable<Page<DeletedCertificateItem>> getDeletedCertificatesAsync(final String vaultBaseUrl, final Integer maxresults, final Boolean includePending) {
          return getDeletedCertificatesWithServiceResponseAsync(vaultBaseUrl, maxresults, includePending)
              .map(new Func1<ServiceResponse<Page<DeletedCertificateItem>>, Page<DeletedCertificateItem>>() {
                  @Override
                  public Page<DeletedCertificateItem> call(ServiceResponse<Page<DeletedCertificateItem>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists the deleted certificates in the specified vault currently available for recovery.
  The GetDeletedCertificates operation retrieves the certificates in the current vault which are in a deleted state and ready for recovery or purging. This operation includes deletion-specific information. This operation requires the certificates/get/list permission. This operation can only be enabled on soft-delete enabled vaults.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param maxresults Maximum number of results to return in a page. If not specified the service will return up to 25 results.
  @param includePending Specifies whether to include certificates which are not completely provisioned.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;DeletedCertificateItem&gt; object