Okla. Stat. tit. 22, § 22-270: Witnesses to give undertaking

On holding the defendant to answer the magistrate may take from

each of the material witnesses examined before him on the part of

the state, a written undertaking, without surety, to the effect that

he will appear and testify at the court to which the complaint and

deposition, if any are to be sent or that he will forfeit such sum

as the magistrate may fix and determine.