code: def put_retention_policy(awsclient, log_group_name, retention_in_days):
      
      try:
          # Note: for AWS Lambda the log_group is created once the first
          # log event occurs. So if the log_group does not exist we create it
          create_log_group(awsclient, log_group_name)
      except GracefulExit:
          raise
      except Exception:
          # TODO check that it is really a ResourceAlreadyExistsException
          pass
  
      client_logs = awsclient.get_client('logs')
      response = client_logs.put_retention_policy(
          logGroupName=log_group_name,
          retentionInDays=retention_in_days
      )
docs: Sets the retention of the specified log group
      if the log group does not yet exist than it will be created first.
  
      :param log_group_name: log group name
      :param retention_in_days: log group name
      :return: