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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 patch(self, *args, **kwargs):
 """Update a relationship"""

        json_data = request.get_json() or {}

        relationship_field, model_relationship_field, related_type_, related_id_field = self._get_relationship_data()

        if 'data' not in json_data:
            raise BadRequest('You must provide data with a "data" route node', source={'pointer': '/data'})
        if isinstance(json_data['data'], dict):
            if 'type' not in json_data['data']:
                raise BadRequest('Missing type in "data" node', source={'pointer': '/data/type'})
            if 'id' not in json_data['data']:
                raise BadRequest('Missing id in "data" node', source={'pointer': '/data/id'})
            if json_data['data']['type'] != related_type_:
                raise InvalidType('The type field does not match the resource type', source={'pointer': '/data/type'})
        if isinstance(json_data['data'], list):
            for obj in json_data['data']:
                if 'type' not in obj:
                    raise BadRequest('Missing type in "data" node', source={'pointer': '/data/type'})
                if 'id' not in obj:
                    raise BadRequest('Missing id in "data" node', source={'pointer': '/data/id'})
                if obj['type'] != related_type_:
                    raise InvalidType('The type provided does not match the resource type',
                                      source={'pointer': '/data/type'})

        self.before_patch(args, kwargs, json_data=json_data)

        obj_, updated = self._data_layer.update_relationship(json_data,
                                                             model_relationship_field,
                                                             related_id_field,
                                                             kwargs)

        status_code = 200
        result = {'meta': {'message': 'Relationship successfully updated'}}

        if updated is False:
            result = ''
            status_code = 204

        final_result = self.after_patch(result, status_code)

        return final_result