<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def configure_replacefor(self, ns, definition):
 """ Register a replace-for relation endpoint. For typical usage, this relation is not strictly required; once an object exists and has its own ID, it is better to operate on it directly via dedicated CRUD routes. However, in some cases, the composite key of (subject_id, object_id) is required to look up the object. This happens, for example, when using DynamoDB where an object which maintains both a hash key and a range key requires specifying them both for access. The definition's func should be a replace function, which must: - accept kwargs for the new instance replacement parameters - return the instance :param ns: the namespace :param definition: the endpoint definition """

        @self.add_route(ns.relation_path, Operation.ReplaceFor, ns)
        @request(definition.request_schema)
        @response(definition.response_schema)
        @wraps(definition.func)
        def replace(**path_data):
            headers = dict()
            request_data = load_request_data(definition.request_schema)
            response_data = require_response_data(definition.func(**merge_data(path_data, request_data)))
            definition.header_func(headers, response_data)
            response_format = self.negotiate_response_content(definition.response_formats)
            return dump_response_data(
                definition.response_schema,
                response_data,
                status_code=Operation.ReplaceFor.value.default_code,
                headers=headers,
                response_format=response_format,
            )

        replace.__doc__ = "Replace a {} relative to a {}".format(pluralize(ns.object_name), ns.subject_name)