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: mod.rs
    path of file: ./repos/cargo-make/src/lib/descriptor
    
    the code of the file until where you have to start completion: //! # descriptor
//!
//! Loads the tasks descriptor.<br>
//! It will first load the default descriptor which is defined in cargo-make
//! internally and af
    
fn check_makefile_min_version(external_descriptor: &str) -> Result<(), String> {
    let value: toml::Value = match toml::from_str(&external_descriptor) {
        Ok(value) => value,
        // If there's an error parsing the file, let the caller function figure
        // it out
        Err(_) => return Ok(()),
    };

    let min_version = value
        .get("config")
        .and_then(|config| config.get("min_version"))
        .and_then(|min_ver| min_ver.as_str());

    if let Some(ref min_version) = min_version {
        if version::is_newer_found(&min_version) {
            return Err(format!(
                "Unable to run, minimum required version is: {}",
                &min_version
            )
            .to_string());
        }
    }

    Ok(())
}