method Command.prototype.requiredOptionimport { Command } from "https://deno.land/x/cmd@v1.2.0/mod.ts"; requiredOption<T>(flags: string,description: string,fn: (value: string, previous: T) => T,defaultValue?: T,)Type ParametersTParametersflags: stringdescription: stringfn: (value: string, previous: T) => ToptionaldefaultValue: T