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: test-iam-service-lib.rs
    path of file: ./repos/aws-doc-sdk-examples/rustv1/examples/iam/tests
    
    the code of the file until where you have to start completion: // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

use aws_config::meta::region::RegionProviderChain;
use aws_sdk_iam::{config::Region, Client as iamClient};
use uuid::Uuid;

#[ignore]
#[tokio::test]
async fn test_create_role() {
    let uuid = Uuid::new_v4().to_string();
    
async fn test_list_users() {
    let region_provider = RegionProviderChain::first_try(Region::new("us-west-2"));

    let shared_config = aws_config::from_env().region(region_provider).load().await;
    let client = iamClient::new(&shared_config);

    let users = iam_service::list_users(&client, None, None, None)
        .await
        .unwrap();
    for user in users.users {
        println!("{}", user.user_name);
    }
}