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: list-all-function-runtimes.rs
    path of file: ./repos/aws-sdk-rust/examples/examples/lambda/src/bin
    
    the code of the file until where you have to start completion: // Copyright Amazon.com, Inc. or its af
    
async fn main() -> Result<(), Error> {
    tracing_subscriber::fmt::init();

    let Opt { language, base } = Opt::parse();
    let language = language.as_deref().unwrap_or_default();
    let verbose = base.verbose;

    let sdk_config = make_config(base).await;

    let ec2_client = aws_sdk_ec2::Client::new(&sdk_config);

    match ec2_client.describe_regions().send().await {
        Ok(resp) => {
            for region in resp.regions.unwrap_or_default() {
                if let Some(region) = region.region_name() {
                    show_lambdas(language, region, verbose)
                        .await
                        .unwrap_or_else(|err| eprintln!("{:?}", err));
                }
            }
        }
        Err(err) => eprintln!("Failed to describe ec2 regions: {}", err),
    }

    Ok(())
}