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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 zext(self, n):
        ''' Zero-extend the variable to n bits.
        
        n bits must be stricly larger than the actual number of bits, or a
        ValueError is thrown
        '''

        if n <= self.nbits:
            raise ValueError("n must be > %d bits" % self.nbits)

        mba_ret = self.__new_mba(n)
        ret = mba_ret.from_cst(0)
        for i in range(self.nbits):
            ret.vec[i] = self.vec[i]
        return mba_ret.from_vec(ret)