code: def configure_searchfor(self, ns, definition):
          
          paginated_list_schema = self.page_cls.make_paginated_list_schema_class(
              ns.object_ns,
              definition.response_schema,
          )()
  
          @self.add_route(ns.relation_path, Operation.SearchFor, ns)
          @qs(definition.request_schema)
          @response(paginated_list_schema)
          @wraps(definition.func)
          def search(**path_data):
              page = self.page_cls.from_query_string(definition.request_schema)
              result = definition.func(**merge_data(path_data, page.to_dict(func=identity)))
              response_data, headers = page.to_paginated_list(result, ns, Operation.SearchFor)
              definition.header_func(headers, response_data)
              response_format = self.negotiate_response_content(definition.response_formats)
              return dump_response_data(
                  paginated_list_schema,
                  response_data,
                  headers=headers,
                  response_format=response_format,
              )
  
          search.__doc__ = "Search for {} relative to a {}".format(pluralize(ns.object_name), ns.subject_name)
docs: Register a relation endpoint.
  
          The definition's func should be a search function, which must:
          - accept kwargs for the query string (minimally for pagination)
          - return a tuple of (items, count, context) where count is the total number of items
            available (in the case of pagination) and context is a dictionary providing any
            needed context variables for constructing pagination links
  
          The definition's request_schema will be used to process query string arguments.
  
          :param ns: the namespace
          :param definition: the endpoint definition