Generate a Context Parameters object based on the instance's
        configuration.
        We do not use the hlapi currently, but the rfc3413.oneliner.cmdgen
        accepts Context Engine Id (always None for now) and Context Name parameters.

def get_context_data(cls, instance):
        '''
        Generate a Context Parameters object based on the instance's
        configuration.
        We do not use the hlapi currently, but the rfc3413.oneliner.cmdgen
        accepts Context Engine Id (always None for now) and Context Name parameters.
        '''

        context_engine_id = None
        context_name = ''

        if "user" in instance:
            if 'context_engine_id' in instance:
                context_engine_id = OctetString(instance['context_engine_id'])
            if 'context_name' in instance:
                context_name = instance['context_name']

        return context_engine_id, context_name