code: def GetBatchJob(client, batch_job_id):
    
    batch_job_service = client.GetService('BatchJobService', 'v201809')
  
    selector = {
        'fields': ['Id', 'Status', 'DownloadUrl'],
        'predicates': [
            {
                'field': 'Id',
                'operator': 'EQUALS',
                'values': [batch_job_id]
            }
        ]
    }
  
    return batch_job_service.get(selector)['entries'][0]
docs: Retrieves the BatchJob with the given id.
  
    Args:
      client: an instantiated AdWordsClient used to retrieve the BatchJob.
      batch_job_id: a long identifying the BatchJob to be retrieved.
    Returns:
      The BatchJob associated with the given id.