Curve25519.py keygen and signing

Curve25519.py

from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey, Ed25519PublicKey
from cryptography.hazmat.primitives import serialization

def unhex(hexed):
    return b''.fromhex(hexed)

def sign(private_key, message):
    private_bytes = unhex(private_key)
    private_key_raw = Ed25519PrivateKey.generate().from_private_bytes(private_bytes)
    signature = private_key_raw.sign(message.encode()).hex()
    return signature

def verify(signature, public_key, message):
    public_bytes = unhex(public_key)
    public_key_raw = Ed25519PublicKey.from_public_bytes(public_bytes)
    public_key_raw.verify(unhex(signature), message.encode())
    return True

def generate_keypair():
    private_key_raw= Ed25519PrivateKey.generate()
    public_key_raw = private_key_raw.public_key()

    private_bytes = private_key_raw.private_bytes(
        encoding=serialization.Encoding.Raw,
        format=serialization.PrivateFormat.Raw,
        encryption_algorithm=serialization.NoEncryption()
    )

    public_bytes = public_key_raw.public_bytes(
        encoding=serialization.Encoding.Raw,
        format=serialization.PublicFormat.Raw
    )

    keypair_dict = {"private_key": private_bytes.hex(),
                    "public_key": public_bytes.hex()
                    }

    return keypair_dict

if __name__ == "__main__":

    keypair_dict = generate_keypair()

    print (keypair_dict["private_key"])
    print (keypair_dict["public_key"])
    signature = sign(private_key=keypair_dict["private_key"], message="test message")
    print(signature)
    print (verify(message="test message",public_key=keypair_dict["public_key"], signature=signature))