def __init__(self,type, children,
                 context=None,
                 prefix=None,
                 fixers_applied=None):
        assert type >= 256, type
        self.type = type
        self.children = list(children)
        for ch in self.children:
            assert ch.parent is None, repr(ch)
            ch.parent = self
        if prefix is not None:
            self.prefix = prefix
        if fixers_applied:
            self.fixers_applied = fixers_applied[:]
        else:
            self.fixers_applied = None
Check whether a value is in the cache. This is keyed by the
dataset/ETHPy150Open ctxis/canape/CANAPE.Scripting/Lib/lib2to3/pytree.py/Node.__init__--crossover with--dataset/ETHPy150Open erkyrath/tworld/lib/two/propcache.py/PropCache.get_by_object