Retrieve a pull request.
        The authenticated user must have REPO_READ permission
        for the repository that this pull request targets to call this resource.
        :param project:
        :param repository:
        :param pull_request_id: the ID of the pull request within the repository
        :return:

def get_pullrequest(self, project, repository, pull_request_id):
        """
        Retrieve a pull request.
        The authenticated user must have REPO_READ permission
        for the repository that this pull request targets to call this resource.
        :param project:
        :param repository:
        :param pull_request_id: the ID of the pull request within the repository
        :return:
        """
        url = 'rest/api/1.0/projects/{project}/repos/{repository}/pull-requests/{pullRequestId}'.format(project=project,
                                                                                                        repository=repository,
                                                                                                        pullRequestId=pull_request_id)
        return self.get(url)