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: test_prelude.rs
    path of file: ./repos/rusty-razor/razor-chase/src
    
    the code of the file until where you have to start completion: use crate::chase::{r#impl::basic, r#impl::collapse, *};
use itertools::Itertools;
use razor_fol::syntax::{term::Complex, Const, Func, Pred, Theory, Var, FOF};
use std::{fmt, fs::File, io::Read};

pub fn equal_sets<T: Eq>(first: &[T], second: &[T]) -> bool {
    first.iter().all(|e| second.contains(e)) && second.iter().all(|e| first.contains(e))
}

// Variables
pub fn _u
    
pub fn print_collapse_model(model: collapse::ColModel) -> String {
    let elements: Vec<String> = model
        .domain()
        .iter()
        .sorted()
        .iter()
        .map(|e| {
            let witnesses: Vec<String> = model.witness(e).iter().map(|w| w.to_string()).collect();
            let witnesses = witnesses.into_iter().sorted();
            format!(
                "{} -> {}",
                witnesses.into_iter().sorted().join(", "),
                e.get()
            )
        })
        .collect();
    let domain: Vec<String> = model.domain().iter().map(|e| e.get().to_string()).collect();
    let facts: Vec<String> = model.facts().iter().map(|e| e.to_string()).collect();
    format!(
        "Domain: {{{}}}\nFacts: {}\n{}",
        domain.into_iter().sorted().join(", "),
        facts.into_iter().sorted().join(", "),
        elements.join("\n")
    )
}