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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 merge_extinfo(service, extinfo):
 """Merge extended host information into a service :param service: the service to edit :type service: alignak.objects.service.Service :param extinfo: the external info we get data from :type extinfo: alignak.objects.serviceextinfo.ServiceExtInfo :return: None """

        properties = ['notes', 'notes_url', 'icon_image', 'icon_image_alt']
        # service properties have precedence over serviceextinfo properties
        for prop in properties:
            if getattr(service, prop) == '' and getattr(extinfo, prop) != '':
                setattr(service, prop, getattr(extinfo, prop))