# Append a bunch of elements at the end of the template with separations.
	# see `add`.
	#
	#     var t = new Template
	#     t.add_list(["1", "2", "3"], ", ", " and ")
	#     assert t.write_to_string == "1, 2 and 3"
	fun add_list(elements: Collection[Writable], sep, last_sep: Writable) do
		var last = elements.length - 2
		var i = 0
		for e in elements do
			content.add e
			if i < last then
				content.add sep
			else if i == last then
				content.add last_sep
			end
			i += 1
		end
	end