import base58


class KeyExtension:
    def get_private_key_from_wif(self, wif: str):
        decoded = base58.b58decode_check(wif)
        if len(decoded) != 34 or decoded[0] != 0x80 or decoded[-1] != 0x01:
            raise ValueError("Incorrect WIF private key")

        private_key = decoded[1:-1]
        return private_key