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Give a counterexample to show that the following construction fails to prove that the class of context-free languages is closed under star. Let $A$ be a $\text{CFL}$ that is generated by the $\text{CFG}$  $G = (V, \Sigma, R, S).$ Add the new rule $S\rightarrow SS$ and call  the resulting grammar $G'.$This grammar is supposed to generate $A^{*}.$

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