Function sign_pss_with_salt_digest 

fn sign_pss_with_salt_digest<T, D>(
    blind_rng: Option<&mut T>,
    priv_key: &RsaPrivateKey,
    hashed: &[u8],
    salt: &[u8],
) -> Result<Vec<u8>>
where
    T: TryCryptoRng + ?Sized,
    D: Digest + FixedOutputReset,