code: def delete_pull_request_status(self, repository_id, pull_request_id, status_id, project=None):
          
          route_values = {}
          if project is not None:
              route_values['project'] = self._serialize.url('project', project, 'str')
          if repository_id is not None:
              route_values['repositoryId'] = self._serialize.url('repository_id', repository_id, 'str')
          if pull_request_id is not None:
              route_values['pullRequestId'] = self._serialize.url('pull_request_id', pull_request_id, 'int')
          if status_id is not None:
              route_values['statusId'] = self._serialize.url('status_id', status_id, 'int')
          self._send(http_method='DELETE',
                     location_id='b5f6bb4f-8d1e-4d79-8d11-4c9172c99c35',
                     version='5.1-preview.1',
                     route_values=route_values)
docs: DeletePullRequestStatus.
          [Preview API] Delete pull request status.
          :param str repository_id: The repository ID of the pull request’s target branch.
          :param int pull_request_id: ID of the pull request.
          :param int status_id: ID of the pull request status.
          :param str project: Project ID or project name