# Load a edge from base
	# Data will be loaded lazily.
	fun load_edge(url: String): NeoEdge do
		if local_edges.has_key(url) then
			var node = local_edges[url]
			if node != null then return node
		end
		var edge = new NeoEdge.from_neo(self, url)
		local_edges[url] = edge
		return edge
	end