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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def GetBatchJob(client, batch_job_id):
 """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. """

  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]