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: edmondskarp.rs
    path of file: ./repos/pathfinding/tests
    
    the code of the file until where you have to start completion: use pathfinding::directed::edmonds_karp::*;
use std::collections::HashMap;

/// Return a list of edges with their capacities.
fn successors_wikipedia() -> Vec<((char, char), i32)> {
    vec![
        ("AB", 3),
        ("AD", 3),
    
fn modified<EK: EdmondsKarp<i32>>() {
    // Graph is:
    //
    // 0 -(6)-> 1 -(5)-> 2 -(7)-> 3
    // |                          ^
    // +--(4)-> 4 -(8)-> 5 -(9)---+
    //
    // Upper branch has capacity 5, lower branch 4.
    let mut ek = EK::new(6, 0, 3);
    ek.set_capacity(0, 1, 6);
    ek.set_capacity(1, 2, 5);
    ek.set_capacity(2, 3, 7);
    ek.set_capacity(0, 4, 4);
    ek.set_capacity(4, 5, 8);
    ek.set_capacity(5, 3, 9);
    assert_eq!(ek.augment().1, 9);
    // Set lower branch capacity to 5.
    ek.set_capacity(0, 4, 5);
    assert_eq!(ek.augment().1, 10);
    // Try setting lower branch individual capacities
    // to 4 one at a time.
    for &(from, to) in &[(0, 4), (4, 5), (5, 3)] {
        ek.set_capacity(from, to, 4);
        assert_eq!(ek.augment().1, 9);
        ek.set_capacity(from, to, 5);
        assert_eq!(ek.augment().1, 10);
    }
    // Set capacity 0->4 to 4.
    ek.set_capacity(0, 4, 4);
    assert_eq!(ek.augment().1, 9);
    // Add a branch 1->4 of 2.
    ek.set_capacity(1, 4, 2);
    assert_eq!(ek.augment().1, 10);
}