mvc_playground.swift

import UIKit

// Module

class FeedViewController: UIViewController {
    
    let model = FeedModel()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        model.load {
            [weak self] (err) in
            if err != nil {
                // Handle Error
            } else {
                self?.reload()
            }
        }
    }
    
    private func reload() {
        //  .....
    }
    
}

class FeedModel {
    
    var items: [Any] = []
    
    func load(_ compl: (Error?) -> Void) {
        
    }
    
    func save_ compl: (Error?) -> Void) {
    
    }
    
}