def set_identifiers(self, data):
        """
        Sets the identifier(s) within the instance data.

        The identifier name(s) is/are determined from the ``ResourceDetails``
        instance hanging off the class itself.

        :param data: The value(s) to be set.
        :param data: dict
        """
        for id_info in self._details.identifiers:
            var_name = id_info['var_name']
            self._data[var_name] = data.get(var_name)

        # FIXME: This needs to likely kick off invalidating/rebuilding
        #        relations.
        #        For now, just remove them all. This is potentially inefficient
        #        but is nicely lazy if we don't need them & prevents stale data
        #        for the moment.
        self._relations = {}