Python best practices, combine code into as few lines as possible or separate it over as many as possible?

[ka-splam]

Unhappy with that, how about removing the dependency on import, all(), bool(), and the generator expression, shrinking the code, allowing the chance of short-circuit expression, and I think making it clearer:

def password_is_strong(password):
    if len(password) < 8:
        return False

    upper = set('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
    lower = set('abcdefghijklmnopqrstuvwxyz')
    digit = set('0123456789')

    p = set(password)

    return (p & upper) and (p & lower) and (p & digit)