fn sign_holder_htlc_transaction(
&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
secp_ctx: &Secp256k1<secp256k1::All>
) -> Result<Signature, ()> {
fn sign_holder_htlc_transaction(
&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
secp_ctx: &Secp256k1<secp256k1::All>
) -> Result<Signature, ()> {