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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 differentiate(self, n=1):
 """ n-th derivative, default 1. """

        ak = self.coefficients()
        a_, b_ = self.domain()
        for _ in range(n):
            ak = self.differentiator(ak)
        return self.from_coeff((2./(b_-a_))**n*ak, domain=self.domain())