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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 update(cls, request_inquiry_id, monetary_account_id=None, status=None, custom_headers=None):
 """ Revoke a request for payment, by updating the status to REVOKED. :type user_id: int :type monetary_account_id: int :type request_inquiry_id: int :param status: The status of the RequestInquiry. Ignored in POST requests but can be used for revoking (cancelling) the RequestInquiry by setting REVOKED with a PUT request. :type status: str :type custom_headers: dict[str, str]|None :rtype: BunqResponseRequestInquiry """


        if custom_headers is None:
            custom_headers = {}

        api_client = client.ApiClient(cls._get_api_context())

        request_map = {
            cls.FIELD_STATUS: status
        }
        request_map_string = converter.class_to_json(request_map)
        request_map_string = cls._remove_field_for_request(request_map_string)

        request_bytes = request_map_string.encode()
        endpoint_url = cls._ENDPOINT_URL_UPDATE.format(cls._determine_user_id(),
                                                       cls._determine_monetary_account_id(
                                                           monetary_account_id),
                                                       request_inquiry_id)
        response_raw = api_client.put(endpoint_url, request_bytes,
                                      custom_headers)

        return BunqResponseRequestInquiry.cast_from_bunq_response(
            cls._from_json(response_raw, cls._OBJECT_TYPE_PUT)
        )