function assertExistsimport { assertExists } from "https://deno.land/x/fastro@v0.70.5/server/deps.ts"; assertExists<T>(actual: T, msg?: string): asserts actual is NonNullable<T>Make an assertion that actual is not null or undefined. If not then throw. Type ParametersTParametersactual: Toptionalmsg: stringReturnsasserts actual is NonNullable<T>