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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 context(self, key, method):
 """A helper method to attach a value within context. :param key: the key attached to the context. :param method: the constructor function. :return: the value attached to the context. """

        ctx = stack.top
        if ctx is not None:
            if not hasattr(ctx, key):
                setattr(ctx, key, method())
            return getattr(ctx, key)