def derive_from_seed(self, offset):
seed = int(hexlify(bytes(self)).decode("<STR_LIT:ascii>"), <NUM_LIT:16>)<EOL>z = int(hexlify(offset).decode("<STR_LIT:ascii>"), <NUM_LIT:16>)<EOL>order = ecdsa.SECP256k1.order<EOL>secexp = (seed + z) % order<EOL>secret = "<STR_LIT>" % secexp<EOL>if len(secret) < <NUM_LIT:64>: <EOL><INDENT>secret = ("<STR_LIT:0>" * (<NUM_LIT:64>-len(secret))) + secret<EOL><DEDENT>return PrivateKey(secret, prefix=self.pubkey.prefix)<EOL>
Derive private key using "generate_from_seed" method.
            Here, the key itself serves as a `seed`, and `offset`
            is expected to be a sha256 digest.