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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 read(self, cnt=None):
 """Read and decrypt."""

        if cnt > 8 * 1024:
            raise BadRarFile('Bad count to header decrypt - wrong password?')

        # consume old data
        if cnt <= len(self.buf):
            res = self.buf[:cnt]
            self.buf = self.buf[cnt:]
            return res
        res = self.buf
        self.buf = EMPTY
        cnt -= len(res)

        # decrypt new data
        blklen = 16
        while cnt > 0:
            enc = self.f.read(blklen)
            if len(enc) < blklen:
                break
            dec = self.ciph.decrypt(enc)
            if cnt >= len(dec):
                res += dec
                cnt -= len(dec)
            else:
                res += dec[:cnt]
                self.buf = dec[cnt:]
                cnt = 0

        return res