(a) For purposes of coverage under Part 2 (commencing with Section 2601) of Division 1, “employment” does not include services performed as an intermittent or adjunct instructor at a postsecondary educational institution which meets the requirements of Article 8 (commencing with Section 94900) of Chapter 7 of Part 59 of the Education Code if the intermittent or adjunct instructor and the employing unit enter a written contract with the following provisions:

1. (1) That any federal or state income tax liability shall be the responsibility of the party providing the services.
2. (2) That no disability insurance coverage is provided under the contract.
3. (3) That the party performing the services certifies that he or she is doing so as a secondary occupation or as a supplemental source of income.