'Flush this instance from the instance cache. Use
`force` to override the result of at_idmapper_flush() for the object.'

def flush_from_cache(self, force=False):

    pk = self._get_pk_val()
    if pk:
        if (force or self.at_idmapper_flush()):
            self.__class__.__dbclass__.__instance_cache__.pop(pk, None)
