default Page<String> listAllValidDatasets(String accountName, String containerName, String pageToken)
      throws AccountServiceException {
    throw new UnsupportedOperationException("This method is not supported");
  }
List all datasets under a container.
@param accountName The name of the parent account.
@param containerName The name of the container.
@param pageToken the start point to list the dataset, if it's null, will start at the beginning.
@return a page of all valid datasets under the container start with page token.
@throws AccountServiceException
ambry-api/src/main/java/com/github/ambry/account/AccountService.java