Function zcash_proofs::load_parameters

pub fn load_parameters(
    spend_path: &Path, 
    output_path: &Path, 
    sprout_path: Option<&Path>
) -> (Parameters<Bls12>, PreparedVerifyingKey<Bls12>, Parameters<Bls12>, PreparedVerifyingKey<Bls12>, Option<PreparedVerifyingKey<Bls12>>)