Inconsistent seed handling

[jimfcarroll]

Using derive_keypair provides different results than every other XRP system. As an example, running:

from xrpl.core.keypairs import derive_keypair, derive_classic_address

# Your XRP seed (starting with 'shf')
seed = "shfMySeed"

# Derive private and public keys
private_key, public_key = derive_keypair(seed)

# Derive the XRP address from the public key
classic_address = derive_classic_address(public_key)

print("XRP Address:", classic_address)

Generates a different XRP Address than ripple-lib.js, Guarda, and bithomp, all of which, when I give it my 'shf...' seed (secp256k1), generate the same XRP Address.

I tried supplying it both algorithms and setting validator both ways and none of the resulting XRP Addresses matched the ones consistently generated by all the other options.

I'm not sure if this is a bug, I'm using it wrong, or my expectations are wrong. Any help would be appreciated. I'm trying to manage an existing wallet with a few funds in it already based on a stored key.