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: main.rs
    path of file: ./repos/exonum/examples/sample_runtime/src
    
    the code of the file until where you have to start completion: // Copyright 2020 The Exonum Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distribu
    
fn node_config() -> (NodeConfig, Keys) {
    let keys = Keys::random();
    let validator_keys = vec![ValidatorKeys::new(keys.consensus_pk(), keys.service_pk())];
    let consensus = ConsensusConfig::default().with_validator_keys(validator_keys);

    let api_address = "0.0.0.0:8000".parse().unwrap();
    let api_cfg = NodeApiConfig {
        public_api_address: Some(api_address),
        ..Default::default()
    };

    let peer_address = "0.0.0.0:2000";

    let node_config = NodeConfig {
        listen_address: peer_address.parse().unwrap(),
        consensus,
        external_address: peer_address.to_owned(),
        network: Default::default(),
        connect_list: Default::default(),
        api: api_cfg,
        mempool: Default::default(),
        thread_pool_size: Default::default(),
    };
    (node_config, keys)
}