Lab 8.2 - Serial Execution

Hi!

I'm having difficulty finding a solution for LAB 8.2

The following is the content of the serial.js file.

'use strict';
const { promisify } = require('util');

const print = (err, contents) => {
  if (err) console.error(err);
  else console.log(contents);
};

const opA = (cb) => {
  setTimeout(() => {
    cb(null, 'A');
  }, 500);
};

const opB = (cb) => {
  setTimeout(() => {
    cb(null, 'B');
  }, 250);
};

const opC = (cb) => {
  setTimeout(() => {
    cb(null, 'C');
  }, 125);
};

The task is the following
Call the functions in such a way that A then B then C is printed out.

So I have wrapped opA, opB, opC functions with promisify and using async, await.

This is what my code looks like

'use strict';
const { promisify } = require('util');

const print = (err, contents) => {
  if (err) console.error(err);
  else console.log(contents);
};

const opA = promisify((cb) => {
  setTimeout(() => {
    cb(null, 'A');
  }, 500);
});

const opB = promisify((cb) => {
  setTimeout(() => {
    cb(null, 'B');
  }, 250);
});

const opC = promisify((cb) => {
  setTimeout(() => {
    cb(null, 'C');
  }, 125);
});

async function run() {
  await opA(print);
  await opB(print);
  await opC(print);
}

run().catch(console.log);

It should print A, B and C. But when I run this, it only prints A and exits without any error.

Can someone help me figure out what am I doing wrong here?