<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def configure_extensions(app):
 """ Configure application extensions """


    db.init_app(app)

    app.wsgi_app = ProxyFix(app.wsgi_app)

    assets.init_app(app)
    for asset in bundles:
        for (name, bundle) in asset.iteritems():
            assets.register(name, bundle)

    login_manager.login_view = 'frontend.login'
    login_manager.login_message_category = 'info'

    @login_manager.user_loader
    def load_user(id):
        return User.query.get(int(id))

    login_manager.init_app(app)

    cache.init_app(app)
    migrate.init_app(app, db)
    toolbar.init_app(app)