args = [
    {
        'type':  'INT_LITERAL',
        'value': '21',
        'key':   'NUM_SCRIPTS'
    },
    {
        'type':  'INT_LITERAL',
        'value': '20',
        'key':   'NUM_CSS'
    }
]

format = 'Your page has {{NUM_SCRIPTS}} blocking script resources and {{NUM_CSS}} blocking CSS resources. This causes a delay in rendering your page.'