# Get the Github milestone with `id`.
	#
	# Returns `null` if the milestone cannot be found.
	#
	# ~~~nitish
	# var api = new GithubAPI(get_github_oauth)
	# var repo = api.get_repo("nitlang/nit")
	# assert repo != null
	# var stone = api.get_milestone(repo, 4)
	# assert stone.title == "v1.0prealpha"
	# ~~~
	fun get_milestone(repo_slug: String, id: Int): nullable Milestone do
		return get("/repos/{repo_slug}/milestones/{id}").as(nullable Milestone)
	end