# Build a new `MGroup` from a `node`.
	#
	# REQUIRE `node.labels.has("MGroup")`
	private fun to_mgroup(model: Model, node: NeoNode): MGroup do
		var m = mentities.get_or_null(node.id.as(Int))
		if m isa MGroup then return m

		assert node.labels.has("MGroup")
		var location = to_location(node["location"].to_s)
		var mpackage = to_mpackage(model, node.out_nodes("PROJECT").first)
		var parent: nullable MGroup = null
		var out = node.out_nodes("PARENT")
		if not out.is_empty then
			parent = to_mgroup(model, out.first)
		end
		var mgroup = new MGroup(node["name"].to_s, location, mpackage, parent)
		mentities[node.id.as(Int)] = mgroup
		set_doc(node, mgroup)
		return mgroup
	end