Better error message for `MultiCodeString` `is_in()` and `is_not_in()` #5765

	---
	name: CI

	on:
	push:
	branches:
	- main
	pull_request:

	jobs:
	check:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4
	- uses: opensafely-core/setup-action@v1
	with:
	install-just: true
	python-version: "3.11"
	- name: Set up development environment
	run: just devenv
	- name: Check formatting and linting rules
	run: just check

	test:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4
	- uses: opensafely-core/setup-action@v1
	with:
	install-just: true
	python-version: "3.11"
	- name: Set up development environment
	run: just devenv
	- name: Run tests
	run: \|
	just test-all

	tag-new-version:
	# This uses `conventional commits` to generate tags. A full list
	# of valid prefixes is here:
	# https://github.com/commitizen/conventional-commit-types/blob/master/index.json
	#
	# fix, perf -> patch release
	# feat -> minor release
	# BREAKING CHANGE in footer -> major release
	#
	# anything else (docs, refactor, etc) does not create a release
	if: github.ref == 'refs/heads/main' && github.event_name != 'pull_request'
	needs: [check, test]
	runs-on: ubuntu-latest
	outputs:
	tag: ${{ steps.tag.outputs.new_version }}
	steps:
	- uses: actions/checkout@v4
	with:
	fetch-depth: 0
	- name: Bump version and push tag
	id: tag
	uses: mathieudutour/github-tag-action@a22cf08638b34d5badda920f9daf6e72c477b07b #v6.2
	with:
	github_token: ${{ secrets.GITHUB_TOKEN }}
	default_bump: false
	release_branches: main

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