Unable to get array from chrome.storage

Whenever I try to get data from chrome.storage, it returns undefined.

chrome.storage.sync.get('courses', function(result) {
      currentCourses = result.courses
      console.log(currentCourses)
      currentCourses.push(coursename)
      chrome.storage.sync.set({courses: currentCourses}, function() {
        alert(`Course "${coursename}" has been added !`)
      });
}

userCourses = async () => {
  await chrome.storage.sync.get('courses', function(result) {
      return(result.courses)
  });
}
courseData = userCourses()
console.log(courseData)

I found an answer here on stack overflow, but it is giving the same error. I am new to JS, and not comfortable with Promises.

I tried the example from the official docs, but it is also giving the same error as below. Can someone help me with a solution, or modify my code ?

Wrap the call to storage in a promise and await it:

function getStorageValuePromise(key) {
  return new Promise((resolve) => {
    chrome.storage.sync.get(key, resolve);
  });
}

await getStorageValuePromise('val');