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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_raise_brok(self, host_name, service_name=''):
 """Get a start downtime brok :param host_name: host concerned by the downtime :type host_name :param service_name: service concerned by the downtime :type service_name :return: brok with wanted data :rtype: alignak.brok.Brok """

        data = self.serialize()
        data['host'] = host_name
        if service_name != '':
            data['service'] = service_name

        return Brok({'type': 'downtime_raise', 'data': data})