How to add map control with leaflet?
===

I'm struggling with turning on the Map Control in Leaflet.

Staring at the example doesn't seem to help.  I know I must be making a stupid mistake, but I can't figure it out.

http://leaflet.cloudmade.com/examples/layers-control.html

I've got my map, and it loads, displays ok, but at the `addTo(map)` method I get the error:

> Uncaught TypeError: Cannot call method 'addTo' of undefined

Any ideas what I'm missing?

    var osmUrl='http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
    var osmAttrib='Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors';
    var street_layer = new L.TileLayer(osmUrl, {minZoom: 8, maxZoom: 18, attribution: osmAttrib});
    map = new L.Map('map',{
                    center: initial_center,
                    zoom: initial_zoom,
                    layers: mapLayersList    
    });
    var baseMaps = {"Streets": street_layer};
    L.Control.Layers(baseMaps, null).addTo(map);
            