Function grin_core::libtx::aggsig::sign_with_blinding

pub fn sign_with_blinding(
    secp: &Secp256k1, 
    msg: &Message, 
    blinding: &BlindingFactor, 
    pubkey_sum: Option<&PublicKey>
) -> Result<Signature, Error>

Just a simple sig, creates its own nonce, etc