You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: multi_ed25519_test.rs
    path of file: ./repos/diem/crates/diem-crypto/src/unit_tests
    
    the code of the file until where you have to start completion: // Copyright (c) The Diem Core Contributors
// SPDX-License-Identifier: Apache-2.0

use crate::{
    ed25519::{Ed25519PrivateKey, Ed25519PublicKey, ED25519_PUBLIC_KEY_LENGTH},
    multi_ed25519::{
    
fn test_successful_signature_serialization(private_keys: &[Ed25519PrivateKey], threshold: u8) {
    let multi_private_key = MultiEd25519PrivateKey::new(private_keys.to_vec(), threshold).unwrap();
    let multi_public_key = MultiEd25519PublicKey::from(&multi_private_key);
    let multi_signature = multi_private_key.sign(message());

    // Serialize then Deserialize.
    let multi_signature_serialized =
        MultiEd25519Signature::try_from(&multi_signature.to_bytes()[..]);
    assert!(multi_signature_serialized.is_ok());
    let multi_signature_serialized_unwrapped = multi_signature_serialized.unwrap();
    assert_eq!(multi_signature, multi_signature_serialized_unwrapped);
    // Ensure that the signature verifies.
    assert!(multi_signature.verify(message(), &multi_public_key).is_ok());
}