// Rust-101, Part 06: Copy, Lifetimes
// ==================================
// Rust-101, Part 06: Copy, Lifetimes
// ==================================
// Now we can write `vec_min`.
fn vec_min(v: &Vec<BigInt>) -> Option<BigInt> {
let mut min: Option<BigInt> = None;
// Now we can write `vec_min`.
fn vec_min(v: &Vec<BigInt>) -> Option<BigInt> {
let mut min: Option<BigInt> = None;