Although the statute provides for the invalidation of contracts made in contravention of the statute, it does not create a private right of action, as the statutory language focuses on the regulated party, a single invalidation would invalidate all other contracts, and the law specifically vests discretion to enforce in an agency, either on its own motion or on application.
http://cdn.ca9.uscourts.gov/datastore/opinions/2018/07/12/17-15435.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.