code: @Override
      public UpdatePullRequestDescriptionResult updatePullRequestDescription(UpdatePullRequestDescriptionRequest request) {
          request = beforeClientExecution(request);
          return executeUpdatePullRequestDescription(request);
      }
docs: <p>
  Replaces the contents of the description of a pull request.
  </p>
  
  @param updatePullRequestDescriptionRequest
  @return Result of the UpdatePullRequestDescription operation returned by the service.
  @throws PullRequestDoesNotExistException
  The pull request ID could not be found. Make sure that you have specified the correct repository name and
  pull request ID, and then try again.
  @throws InvalidPullRequestIdException
  The pull request ID is not valid. Make sure that you have provided the full ID and that the pull request
  is in the specified repository, and then try again.
  @throws PullRequestIdRequiredException
  A pull request ID is required, but none was provided.
  @throws InvalidDescriptionException
  The pull request description is not valid. Descriptions are limited to 1,000 characters in length.
  @throws PullRequestAlreadyClosedException
  The pull request status cannot be updated because it is already closed.
  @sample AWSCodeCommit.UpdatePullRequestDescription
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/codecommit-2015-04-13/UpdatePullRequestDescription"
  target="_top">AWS API Documentation</a>