'Sets multiple keys and values from a mapping.
:param mapping: a mapping with the keys/values to set.
:param timeout: the cache timeout for the key in seconds (if not
specified, it uses the default timeout). A timeout of
0 idicates that the cache never expires.
:returns: Whether all given keys have been set.
:rtype: boolean'

def set_many(self, mapping, timeout=None):

    rv = True
    for (key, value) in _items(mapping):
        if (not self.set(key, value, timeout)):
            rv = False
    return rv
