Okla. Stat. tit. 82 § 641
Before receiving the aforesaid "Assessment Book" the treasurer of each county in which lands or other property of the district are located, shall execute to the board of directors of the district a bond with at least two good and sufficient sureties or a surety company, and which shall be paid for by the district in a sum not less than the probable amount of any annual levy of said assessment to be collected by him during any one (1) year, on condition that said treasurer shall pay over and account for all assessments so collected by him according to law. Said bond after approval by said board of directors shall be deposited with the secretary of the board of directors who shall produce same for inspection and use as evidence whenever and wherever lawfully requested so to do.
Okla. Stat. tit. 82, § 641