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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cached(func, instance, args, kwargs):
 """Simple decorator to cache result of method calls without args."""

    cache = getattr(instance, "__cache", None)
    if cache is None:
        instance.__cache = cache = {}
    try:
        return cache[func]
    except KeyError:
        cache[func] = result = func(*args, **kwargs)
        return result