Add a method in solutions/18_iterators/iterators4.rs #1338

	name: Rustlings Tests

	on:
	push:
	branches: [main]
	pull_request:
	branches: [main]

	env:
	CARGO_TERM_COLOR: always

	jobs:
	clippy:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- run: cargo clippy -- --deny warnings
	fmt:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: DavidAnson/markdownlint-cli2-action@v16
	with:
	globs: "exercises/*/.md"
	- name: Run cargo fmt
	run: cargo fmt --all --check
	test:
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os: [ubuntu-latest, windows-latest, macOS-latest]
	steps:
	- uses: actions/checkout@v4
	- uses: swatinem/rust-cache@v2
	- name: Run cargo test
	run: cargo test --workspace
	dev-check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: swatinem/rust-cache@v2
	- name: Run rustlings dev check
	run: cargo run -- dev check --require-solutions

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