How to cache images from listview from firebase swift 3 - swift

Question

I am struggling to comprehend how to cache images in my listview that I have fetched from Firebase. I have checked online and most of the solutions are somewhat different from the style of code I am writing so find it difficult to transfer over. Any solutions would be grateful for the class I have provided below.
class StaffListTableViewCell: UITableViewCell {
#IBOutlet weak var staffFirstAndLastName: UILabel!
#IBOutlet weak var JobTitle: UILabel!
#IBOutlet weak var staffImageView: UIImageView!
var databaseRef: DatabaseReference {
return Database.database().reference()
}
var storageRef: Storage {
return Storage.storage()
}
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func configureCell(teacher: StaffListsSTRUCT) {
//this line of code helps sets the imageviews in the list view to nil before loading.
self.staffImageView.image = nil
self.staffFirstAndLastName.text = teacher.staffName
self.JobTitle.text = teacher.staffJobTitle
let imageURL = teacher.staffImageViewString!
self.storageRef.reference(forURL: imageURL).getData(maxSize: 1 * 1024 * 1024, completion: { (imgData,
error) in
if error == nil {
DispatchQueue.main.async {
if let data = imgData {
self.staffImageView.image = UIImage(data: data)
}
}
} else {
print(error!.localizedDescription)
}
})
}
}