def immutable(self, expr):
    klass = expr.__class__ 
    
    
    result = (klass in self._immutable_classes and 
                (all(self.immutable(c) for c in expr.children()))) or \
             (klass is Attribute and isinstance(expr.type, ImmutableT))
    return result
Get states from the persistent storage to internal cache.
dataset/ETHPy150Open iskandr/parakeet/parakeet/transforms/simplify.py/Simplify.immutable--crossover with--dataset/ETHPy150Open scrapinghub/frontera/frontera/core/components.py/States.fetch