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: mod.rs
    path of file: ./repos/skytable/harness/src/test
    
    the code of the file until where you have to start completion: /*
 * Created on Thu Mar 17 2022
 *
 * This file is a part of Skytable
 * Skytable (formerly known as TerrabaseDB or Skybase) is a free and open-source
 * NoSQL database written by Sayan Nandan ("the Author") with the
 * vision to provide flexibility in data modelling without compromising
 * on performance, queryability or scalability.
 *
 * Copyright (c) 2022, Sayan Nandan <ohsayan@outlook.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT AN
    
fn mk_ca_cert(password: &[u8]) -> Result<(Vec<u8>, Vec<u8>), ErrorStack> {
    let rsa = Rsa::generate(2048)?;
    let key_pair = PKey::from_rsa(rsa)?;

    let mut x509_name = X509NameBuilder::new()?;
    x509_name.append_entry_by_text("C", "US")?;
    x509_name.append_entry_by_text("ST", "CA")?;
    x509_name.append_entry_by_text("O", "Skytable")?;
    x509_name.append_entry_by_text("CN", "sky-harness")?;
    let x509_name = x509_name.build();

    let mut cert_builder = X509::builder()?;
    cert_builder.set_version(2)?;
    let serial_number = {
        let mut serial = BigNum::new()?;
        serial.rand(159, MsbOption::MAYBE_ZERO, false)?;
        serial.to_asn1_integer()?
    };
    cert_builder.set_serial_number(&serial_number)?;
    cert_builder.set_subject_name(&x509_name)?;
    cert_builder.set_issuer_name(&x509_name)?;
    cert_builder.set_pubkey(&key_pair)?;
    let not_before = Asn1Time::days_from_now(0)?;
    cert_builder.set_not_before(&not_before)?;
    let not_after = Asn1Time::days_from_now(365)?;
    cert_builder.set_not_after(&not_after)?;

    cert_builder.append_extension(BasicConstraints::new().critical().ca().build()?)?;
    cert_builder.append_extension(
        KeyUsage::new()
            .critical()
            .key_cert_sign()
            .crl_sign()
            .build()?,
    )?;

    let subject_key_identifier =
        SubjectKeyIdentifier::new().build(&cert_builder.x509v3_context(None, None))?;
    cert_builder.append_extension(subject_key_identifier)?;
    cert_builder.sign(&key_pair, MessageDigest::sha256())?;
    let cert = cert_builder.build().to_pem().unwrap();
    let key_pair = key_pair.private_key_to_pem_pkcs8_passphrase(Cipher::aes_256_cbc(), password)?;
    Ok((cert, key_pair))
}