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: lazy.rs
    path of file: ./repos/polars/py-polars/src/functions
    
    the code of the file until where you have to start completion: use polars::lazy::dsl;
use polars::prelude::*;
use pyo3::exceptions::PyTypeError;
use pyo3::prelude::*;
use pyo3::types::{PyBool, PyBytes, PyFloat, PyInt, PyString};

use crate::conversion::{get_lf, Wrap};
use crate::expr::ToExprs;
use crate::map::lazy::binary_lambda;
use crate::prelude::{vec_extract_wrapped, ObjectValue};
use crate::{map, PyDataFrame, PyExpr, PyLazyFrame, PyPolarsErr, PySeries};

macro_rules! set_unwrapped_or_0 {
    ($($var:ident),+ $(,)?) => {
        $(let $var = $var.map(|e| e.inner).unwrap_or(dsl::lit(0));)+
    };
}

#[pyfunction]
pub fn rolling_corr(
    x: PyExpr,
    y: PyExpr,
    window_size: IdxSize,
    min_periods: IdxS
    
pub fn collect_all_with_callback(lfs: Vec<PyLazyFrame>, lambda: PyObject, py: Python) {
    use polars_core::utils::rayon::prelude::*;

    py.allow_threads(|| {
        polars_core::POOL.install(move || {
            polars_core::POOL.spawn(move || {
                let result = lfs
                    .par_iter()
                    .map(|lf| {
                        let df = lf.ldf.clone().collect()?;
                        Ok(PyDataFrame::new(df))
                    })
                    .collect::<polars_core::error::PolarsResult<Vec<_>>>()
                    .map_err(PyPolarsErr::from);

                Python::with_gil(|py| match result {
                    Ok(dfs) => {
                        lambda.call1(py, (dfs,)).map_err(|err| err.restore(py)).ok();
                    },
                    Err(err) => {
                        lambda
                            .call1(py, (PyErr::from(err).to_object(py),))
                            .map_err(|err| err.restore(py))
                            .ok();
                    },
                })
            })
        });
    });
}