§ 524. Exemption from taxation and execution. The right of a teacher to a pension, an annuity, or a retirement allowance, to the return of contributions, any benefit or right accrued or accruing to any person under the provisions of this article, and the moneys in the various funds created hereunder, are hereby exempt from any state or municipal tax, and shall not be subject to execution, garnishment, attachment or any other process whatsoever, and shall be unassignable except as in this article specifically provided.