Change all fonts except Gizmo to Proxima Nova

gistfile1.js

var doc = context.document;
var page = [doc currentPage];
var layers = [page children];

var font_name = "Proxima Nova";

function check_layer(layer)
{
    if (!layer) return;

    switch ([layer class])
    {
        case MSTextLayer:
            if ([layer fontPostscriptName] == "SSGizmo") log("Gizmo");
            else layer.setFontPostscriptName(font_name);

            break;
        case MSPage:
        case MSLayerGroup:
        case MSArtboardGroup:
            var sublayers = [layer layers];
            break;
            log("This is a group/artboard/page with " + [sublayers count] + " sublayers")
            for(var i=0; i < [sublayers count]; i++)
            {
                var sublayer = sublayers[i];
                check_layer(sublayer);
            }
        break;
    }
}

for (var i = 0; i < [layers count]; i++)
{
    check_layer(layers[i])
}