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: old_config.rs
    path of file: ./repos/zellij/zellij-client/src/old_config_converter
    
    the code of the file until where you have to start completion: // This is a converter from the old yaml config to the new KDL config.
//
// It is supposed to be mostly self contai
    
fn env_yaml_to_env_kdl(env_yaml: &OldEnvironmentVariablesFromYaml) -> String {
    let mut env_kdl = String::new();
    let mut env_vars: Vec<(String, String)> = env_yaml
        .env
        .iter()
        .map(|(name, val)| (name.clone(), val.clone()))
        .collect();
    env_vars.sort_unstable();
    env_kdl.push_str("env {\n");
    for (name, val) in env_vars {
        env_kdl.push_str(&format!("    {} \"{}\"\n", name, val));
    }
    env_kdl.push_str("}\n");
    env_kdl
}