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: create-role.rs
    path of file: ./repos/aws-doc-sdk-examples/rustv1/examples/iam/src/bin
    
    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

#![allow(clippy::result_large_err)]

use aws_config::meta::region::RegionProviderChain;
use aws_sdk_iam::{config::Region, meta::PKG_VERSION, Client, Error};
use clap::Parser;
use std::fs;

#[derive(Debug, Parser)]
struct Opt {
    /// The AWS Region.
    #[structopt(short, long)]
    region: Option<String>,

    /// The name of the role.
    #[structopt(short, long)]
    name: String,

    /// The name of the file containing the policy document.
    #[structopt(short, long)]
    policy_file: String,

    /// Whether to display additional information.
    #[structopt(short, long)]
    verbose: bool,
}

// Creates a role.
// snippet-start:[iam.rust.create-role]
async fn make_role(client: &Client, policy: &str, name: &str) -> String {
    let resp = client
        .create_role()
        .assume_role_policy_document(policy)
        .rol
    
async fn main() -> Result<(), Error> {
    tracing_subscriber::fmt::init();
    let Opt {
        name,
        policy_file,
        region,
        verbose,
    } = Opt::parse();

    let region_provider = RegionProviderChain::first_try(region.map(Region::new))
        .or_default_provider()
        .or_else(Region::new("us-west-2"));
    println!();

    if verbose {
        println!("IAM client version: {}", PKG_VERSION);
        println!(
            "Region:             {}",
            region_provider.region().await.unwrap().as_ref()
        );
        println!("Role name:          {}", &name);
        println!("Policy doc filename {}", &policy_file);
        println!();
    }

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

    // Read policy doc from file as a string
    let policy_doc = fs::read_to_string(policy_file).expect("Unable to read file");

    let response = make_role(&client, policy_doc.as_str(), &name).await;
    println!("{response}");

    Ok(())
}