When using bounds I get a NoneType Error.

[vetostream]

Is there somewhere in my code that's causing this?

{
   "layers": [{
       "id": "countries",
       "src": "TM_WORLD_BORDERS_SIMPL-0.3.shp",
       "filter": {"ISO3": ["FRA", "PHL"]}
    }],
    "bounds": {
        "mode": "polygons",
        "data": {
            "layer": "countries"
        }
    }
}

I get this error:

  cli.py, in render_map()
  71: K.generate(cfg, args.output, preview=args.preview, format=format, stylesheet=css)  kartograph.py, in generate()
  46: _map = Map(opts, self.layerCache, format=format)  map.py, in __init__()
  50: me.bounds_poly = me._init_bounds()  map.py, in _init_bounds()
  198: fbbox = geom_to_bbox(feature.geometry, data["min-area"])  geometry/utils.py, in geom_to_bbox()
  36: minx, miny, maxx, maxy = geom.bounds
'NoneType' object has no attribute 'bounds'