function step1(x: number): Promise<number> { return Promise.resolve(x + 10); }
function step2(x: number): Promise<number> { return Promise.resolve(x * 2); }
function step3(x: number): Promise<string> { return Promise.resolve("resultado: " + x); }

async function processValue(x: number): Promise<string> {
  return step1(x)
    .then(step2)
    .then(step3)
}

export { processValue };