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: dependency_deduplication.rs
    path of file: ./repos/logicsim/src/graph/optimizations
    
    the code of the file until where you have to start completion: use super::super::{gate::*, graph_builder::GateGraphBuilder};
use smallvec::SmallVec;
use std::collections::HashMap;
use GateType::*;

/// Removes duplicate dependencies from gates.
/// If the gate is an Xor or Xnor it keeps 1 if there are an odd number of copies
/// or 2 if there are an even number of copies.
pub fn dependency_deduplication_pass(g: &mut GateGraphBuilder) {
    struct WorkItem {
        idx: GateIndex,
        duplicates: SmallVec<[(GateIndex, usize); 2]>,
    }

    let mut work: Vec<WorkItem> = g
        .nodes
        .iter()
        .filter_map(|(idx, gate)| {
            let mut dependency_multi_map = HashMap::<GateIndex, usize>::new();
            // Detect duplicate dependencies and how many times they are duplicated.
            for dependency in gate.dependencies.iter().copied() {
                let entry = dependency_multi_map.entry(dependency).or_default();
                *entry += 1
            }

            let idx = idx.into();
            let duplicates: SmallVec<_> = dependency_multi_map
                .into_iter()
                .filter(|(_, count)| *count > 1)
                .collect();
   
    
pub fn dependency_deduplication_pass(g: &mut GateGraphBuilder) {
    struct WorkItem {
        idx: GateIndex,
        duplicates: SmallVec<[(GateIndex, usize); 2]>,
    }

    let mut work: Vec<WorkItem> = g
        .nodes
        .iter()
        .filter_map(|(idx, gate)| {
            let mut dependency_multi_map = HashMap::<GateIndex, usize>::new();
            // Detect duplicate dependencies and how many times they are duplicated.
            for dependency in gate.dependencies.iter().copied() {
                let entry = dependency_multi_map.entry(dependency).or_default();
                *entry += 1
            }

            let idx = idx.into();
            let duplicates: SmallVec<_> = dependency_multi_map
                .into_iter()
                .filter(|(_, count)| *count > 1)
                .collect();
            if duplicates.is_empty() {
                None
            } else {
                Some(WorkItem { idx, duplicates })
            }
        })
        .collect();

    enum Action {
        Keep1,
        Keep2,
    }
    use Action::*;
    while let Some(WorkItem { idx, duplicates }) = work.pop() {
        let gate_dependencies = &mut g.get_mut(idx).dependencies;
        gate_dependencies.sort();
        gate_dependencies.dedup();
        for (duplicate, count) in duplicates {
            let gate_type = &g.get(idx).ty;
            let action = match gate_type {
                Off | On | Lever => {
                    unreachable!("Off, On, and lever nodes have no dependencies")
                }
                Not => unreachable!("Not gates only have 1 dependency"),

                And | Nand | Or | Nor => Keep1,
                Xor | Xnor => {
                    if count % 2 == 0 {
                        Keep2
                    } else {
                        Keep1
                    }
                }
            };
            if let Keep2 = action {
                g.get_mut(idx).dependencies.push(duplicate)
            }
        }
    }
}