238.15  Exemption of funds from taxation, execution, and assignment.--The pensions, annuities or any other benefits accrued or accruing to any person under the provisions of this chapter and the accumulated contributions and cash securities in the funds created under this chapter are exempted from any state, county or municipal tax of the state, and shall not be subject to execution or attachment or to any legal process whatsoever, and shall be unassignable, except:

(1)  That any teacher who has retired shall have the right and power to authorize in writing the Division of Retirement to deduct from his or her monthly retirement allowance money for the payment of the premiums on group insurance for hospital, medical and surgical benefits, under a plan or plans for such benefits approved in writing by the Insurance Commissioner and Treasurer of the state, and upon receipt of such request the division shall make the monthly payments as directed; and

(2)  As may be otherwise specifically provided for in this chapter.