[kovidgoyal]

I took a quick look, and this is what I came up with:

def classes(classes):
    q = frozenset(classes.split(' '))
    return dict(
        attrs={'class': lambda x: x and frozenset(x.split()).intersection(q)}
    )


class AdvancedUserRecipe1502348373(BasicNewsRecipe):
    title = 'The Federalist'
    oldest_article = 7
    max_articles_per_feed = 100
    no_stylesheets = True
    encoding = 'utf-8'
    use_embedded_content = False
    remove_attributes = ['xmlns', 'lang', 'style', 'width', 'height']

    keep_only_tags = [
        classes('entry-header'),
        classes('wp-post-image post-categories entry-content shortbio'),
    ]

    feeds = [
        ('All', 'http://thefederalist.com/feed/'),
    ]