The right of a person to an annuity or a retirement allowance, to the return of contributions, the annuity, or retirement allowance itself, any optional benefit, any other right or benefit accrued or accruing to any person under this part, and the moneys in the fund created under this part are not subject to execution or any other process whatsoever, except to the extent permitted by Section 704.110 of the Code of Civil Procedure, and are unassignable except as specifically provided in this part.