# Find a previous rating of `self` for `mentity` and `dimension`
	fun find_previous_rating(config: NitwebConfig, mentity: MEntity, dimension: nullable String): nullable StarRating do
		var match = new MongoMatch
		match.eq("mentity", mentity.full_name)
		match.eq("dimension", dimension)
		match.eq("user", login)
		return config.stars.find(match)
	end