pub fn sign_with_aux_rand<C: Signing, ES: Deref>(
ctx: &Secp256k1<C>, msg: &Message, sk: &SecretKey, entropy_source: &ES
) -> Signature where ES::Target: EntropySource {
pub fn sign_with_aux_rand<C: Signing, ES: Deref>(
ctx: &Secp256k1<C>, msg: &Message, sk: &SecretKey, entropy_source: &ES
) -> Signature where ES::Target: EntropySource {