Okla. Stat. tit. 21, § 21-541: Extrajudicial oaths

Every person who takes an oath before an officer or person

authorized to administer judicial oaths, except when such oath is

required or authorized by law, or is required by the provisions of

some contract as the basis of or in proof of a claim, or when the

same has been agreed to be received by some person as proof of any

fact, in the performance of any contract, obligation or duty instead

of other evidence, is guilty of a misdemeanor.