code: @Override
      public DescribeDirectoriesResult describeDirectories(DescribeDirectoriesRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeDirectories(request);
      }
docs: <p>
  Obtains information about the directories that belong to this account.
  </p>
  <p>
  You can retrieve information about specific directories by passing the directory identifiers in the
  <code>DirectoryIds</code> parameter. Otherwise, all directories that belong to the current account are returned.
  </p>
  <p>
  This operation supports pagination with the use of the <code>NextToken</code> request and response parameters. If
  more results are available, the <code>DescribeDirectoriesResult.NextToken</code> member contains a token that you
  pass in the next call to <a>DescribeDirectories</a> to retrieve the next set of items.
  </p>
  <p>
  You can also specify a maximum number of return results with the <code>Limit</code> parameter.
  </p>
  
  @param describeDirectoriesRequest
  Contains the inputs for the <a>DescribeDirectories</a> operation.
  @return Result of the DescribeDirectories operation returned by the service.
  @throws EntityDoesNotExistException
  The specified entity could not be found.
  @throws InvalidParameterException
  One or more parameters are not valid.
  @throws InvalidNextTokenException
  The <code>NextToken</code> value is not valid.
  @throws ClientException
  A client exception has occurred.
  @throws ServiceException
  An exception has occurred in AWS Directory Service.
  @sample AWSDirectoryService.DescribeDirectories
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/ds-2015-04-16/DescribeDirectories" target="_top">AWS API
  Documentation</a>