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/kanata/parser/src/cfg
    
    the code of the file until where you have to start completion: //! This parses the configuration language to create a `kanata_keyberon::layout::Layout` as well as
//! associated metadata to help with processing.
//!
//! How the configuration maps to keyberon:
//!
//! If the mapped keys are defined as:
//!
//! (defsrc
//!     esc  1    2    3    4
//! )
//!
//! and the layers are:
//!
//! (deflayer one
//!  
    
fn parse_u8_with_range(expr: &SExpr, s: &ParsedState, label: &str, min: u8, max: u8) -> Result<u8> {
    expr.atom(s.vars())
        .map(str::parse::<u8>)
        .and_then(|u| u.ok())
        .and_then(|u| {
            assert!(min <= max);
            if u >= min && u <= max {
                Some(u)
            } else {
                None
            }
        })
        .ok_or_else(|| anyhow_expr!(expr, "{label} must be {min}-{max}"))
}