cache, cache_key = _get_cache_parameters(self)

        cache.remove(cache_key)

    def get_value(self, merge=True, createfunc=None):

        """Return the value from the cache for this query.

        Raise KeyError if no value present and no

        createfunc specified.

        """

        cache, cache_key = _get_cache_parameters(self)

        ret = cache.get_value(cache_key, createfunc=createfunc)

        if merge:

            ret = self.merge_result(ret, load=False)

        return ret

    def set_value(self, value):

        """Set the value in the cache for this query."""

        cache, cache_key = _get_cache_parameters(self)

        cache.put(cache_key, value)

    def query(*arg, **kw):

    return query

def get_cache_region(name, region):

    if region not in beaker.cache.cache_regions:

        raise BeakerException('Cache region `%s` not configured '

            'Check if proper cache settings are in the .ini files' % region)

    kw = beaker.cache.cache_regions[region]

    return beaker.cache.Cache._get_cache(name, kw)

def _get_cache_parameters(query):

    """For a query with cache_region and cache_namespace configured,

    return the correspoinding Cache instance and cache key, based

    on this query's current criterion and parameter values.

    """

    if not hasattr(query, '_cache_parameters'):

        raise ValueError("This Query does not have caching "

                         "parameters configured.")

    region, namespace, cache_key = query._cache_parameters

    namespace = _namespace_from_query(namespace, query)

                            None)

    def and_(self, option):

        """Chain another RelationshipCache option to this one.

        While many RelationshipCache objects can be specified on a single

        Query separately, chaining them together allows for a more efficient

        lookup during load.

        """

        self._relationship_options.update(option._relationship_options)

        return self

def _params_from_query(query):

    """Pull the bind parameter values from a query.

    This takes into account any scalar attribute bindparam set up.

    E.g. params_from_query(query.filter(Cls.foo==5).filter(Cls.bar==7)))

    would return [5, 7].

    """

    v = []

    def visit_bindparam(bind):

        value = query._params.get(bind.key, bind.value)

        # lazyloader may dig a callable in here, intended

        # to late-evaluate params after autoflush is called.

        # convert to a scalar value.

        if callable(value):

            value = value()

        v.append(value)

    if query._criterion is not None:

        visitors.traverse(query._criterion, {}, {'bindparam': visit_bindparam})

    return v