pub fn update_revocation_registry(
    cred_def: &CredentialDefinition,
    rev_reg_def: &RevocationRegistryDefinition,
    rev_reg_priv: &RevocationRegistryDefinitionPrivate,
    rev_reg: &RevocationRegistry,
    issued: BTreeSet<u32>,
    revoked: BTreeSet<u32>
) -> Result<(RevocationRegistry, RevocationRegistryDelta)>