method OptionAbstract.prototype.mimport { OptionAbstract } from "https://deno.land/x/careful@v0.1.0/mod.ts"; m<NT>(cb: (v: T) => NT): OptionAbstract<T> | OptionAbstract<NT>Type ParametersNTParameterscb: (v: T) => NTReturnsOptionAbstract<T> | OptionAbstract<NT>