pub(super) fn verify<T: secp256k1::Signing>(
&self, key: &ExpandedKey, secp_ctx: &Secp256k1<T>
) -> Result<(OfferId, Option<Keypair>), ()> {
pub(super) fn verify<T: secp256k1::Signing>(
&self, key: &ExpandedKey, secp_ctx: &Secp256k1<T>
) -> Result<(OfferId, Option<Keypair>), ()> {