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: lib.rs
    path of file: ./repos/Daft/src/daft-dsl/src
    
    the code of the file until where you have to start completion: #![feature(let_chains)]
mod arithmetic;
mod expr;
pub mod functions;
mod lit;
pub mod optimization;
#[cfg(feature = "python")]
mod pyobject;
#[cfg(feature = "python")]
pub mod python;
mod treenode;
pub use common_treenode;
pub use expr::binary_op;
pub use expr::col;
pub use expr::{AggExpr, Expr, ExprRef, Operator};
pub use lit::{lit, null_lit, Litera
    
pub fn register_modules(_py: Python, parent: &PyModule) -> PyResult<()> {
    parent.add_class::<python::PyExpr>()?;

    parent.add_wrapped(wrap_pyfunction!(python::col))?;
    parent.add_wrapped(wrap_pyfunction!(python::lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::date_lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::time_lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::timestamp_lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::decimal_lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::series_lit))?;
    parent.add_wrapped(wrap_pyfunction!(python::udf))?;
    parent.add_wrapped(wrap_pyfunction!(python::eq))?;

    Ok(())
}