Read this and answer the question. If the question is unanswerable, say "unanswerable".

The "formal" interpretation is more widespread than the "substantive" interpretation. Formalists hold that the law must be prospective, well-known, and have characteristics of generality, equality, and certainty. Other than that, the formal view contains no requirements as to the content of the law. This formal approach allows laws that protect democracy and individual rights, but recognizes the existence of "rule of law" in countries that do not necessarily have such laws protecting democracy or individual rights.

How many requirements for content are there for the rule of law under the formalist approach?
no requirements