method Ledger.prototype.withAppimport { Ledger } from "https://dotland.deno.dev/x/polkadot@0.2.45/hw-ledger/index.ts"; withApp<T>(fn: (app: SubstrateApp) => Promise<T>): Promise<T>Type ParametersTParametersfn: (app: SubstrateApp) => Promise<T>ReturnsPromise<T>