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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 get_previous_request(rid):
 """Return the last ceph broker request sent on a given relation @param rid: Relation id to query for request """

    request = None
    broker_req = relation_get(attribute='broker_req', rid=rid,
                              unit=local_unit())
    if broker_req:
        request_data = json.loads(broker_req)
        request = CephBrokerRq(api_version=request_data['api-version'],
                               request_id=request_data['request-id'])
        request.set_ops(request_data['ops'])

    return request