# Retrieve nodes belonging to all the specified `labels`.
	#
	#     var client = new Neo4jClient("http://neo4j:7474")
	#
	#     var andres = new NeoNode
	#     andres.labels.add_all(["Human", "Male"])
	#     client.save_node(andres)
	#     var kate = new NeoNode
	#     kate.labels.add_all(["Human", "Female"])
	#     client.save_node(kate)
	#
	#     var nodes = client.nodes_with_labels(["Human", "Male"])
	#     assert nodes.has(andres)
	#     assert not nodes.has(kate)
	fun nodes_with_labels(labels: Array[String]): Array[NeoNode] do
		assert not labels.is_empty

		# Build the query.
		var buffer = new Buffer
		buffer.append "match (n) where \{label_0\} in labels(n)"
		for i in [1..labels.length[ do
			buffer.append " and \{label_{i}\} in labels(n)"
		end
		buffer.append " return n"
		var query = new CypherQuery.from_string(buffer.write_to_string)
		for i in [0..labels.length[ do
			query.params["label_{i}"] = labels[i]
		end

		# Retrieve the answer.
		var res = cypher(query)
		var nodes = new Array[NeoNode]
		for json in res.as(JsonObject)["data"].as(JsonArray) do
			var obj = json.as(JsonArray).first.as(JsonObject)
			var node = load_node(obj["self"].to_s)
			node.internal_properties = obj["data"].as(JsonObject)
			nodes.add node
		end
		return nodes
	end