Okla. Stat. tit. 74, § 935.3

The Board of Trustees of the Oklahoma Public Employees Retirement System (Board) shall take whatever action is reasonable and necessary to have the defined contribution system authorized by this act to be recognized as a tax-qualified plan as that term is defined by Section 401 et seq. of Title 26 of the United States Code, or any other applicable provisions of federal law. The Board is also authorized to establish a plan or use an existing plan established under Section 457(b) of Title 26 of the United States Code, if it is necessary to carry out the intent of this act. The Board shall take whatever action is reasonable and necessary to obtain confirmation from the Internal Revenue Service that any such 457(b) plan is consistent with the requirements of Section 457(b).