code: @Override
      public DescribeDocumentResult describeDocument(DescribeDocumentRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeDocument(request);
      }
docs: <p>
  Describes the specified Systems Manager document.
  </p>
  
  @param describeDocumentRequest
  @return Result of the DescribeDocument operation returned by the service.
  @throws InternalServerErrorException
  An error occurred on the server side.
  @throws InvalidDocumentException
  The specified document does not exist.
  @throws InvalidDocumentVersionException
  The document version is not valid or does not exist.
  @sample AWSSimpleSystemsManagement.DescribeDocument
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/ssm-2014-11-06/DescribeDocument" target="_top">AWS API
  Documentation</a>