def get_private(self):
        """ Derive private key from the brain key and the current sequence
            number
        """
        encoded = "%s %d" % (self.brainkey, self.sequence)
        a = _bytes(encoded)
        s = hashlib.sha256(hashlib.sha512(a).digest()).digest()
        return PrivateKey(hexlify(s).decode("ascii"), prefix=self.prefix)
Derive private key from the brain key and the current sequence
            number