in Flask, dealing with growing assets in __init__.py file

Question

# New to flask!

I'm working on adding features to a Flask project and it has its assets bundled using the code below in __init__.py file.

js = Bundle('javascripts/leaflet-src.js',
            'javascripts/leaflet.markercluster-src.js',
            'javascripts/handlebars-v3.0.3.js',
            'javascripts/Control.Geocoder.js','javascripts/Control.LinkButton.js',
            'javascripts/underscore-min.js','javascripts/L.Control.Sidebar.js',
            'javascripts/Control.Loading.js', 'javascripts/main.js',
            filters='jsmin',
            output='gen/packed.js')

I'm gonna add more javascript files and this will keep growing and my __init__.py looks ugly.

I work a lot with Ruby in Rails and I like the way assets are managed there. You have an application.js.erb file where you add all the js file names that you want to be included into one application.js file. I could build one such structure for this Flask project too but I would like to know whether there is already a nicer way to manage growing assets in Flask.