`func retrieveAllContact()->[Contact]{`
        `let appDelegate = (UIApplication.shared.delegate) as! AppDelegate`
        `let context = appDelegate.persistentContainer.viewContext`
        `var contact:[NSManagedObject] = []`
        `var contactList:[Contact] = []`

        `let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "CDContact")`
        `do {`
            `contact = try context.fetch(fetchRequest)`

            `for c in contact {`
                `let firstname = c.value(forKey: "firstname") as? String`
                `let lastname = c.value(forKey: "lastname") as? String`
                `let mobileno = c.value(forKey: "mobileno") as? String`
                `contactList.append(Contact(firstname: firstname!, lastname: lastname!, mobileno: mobileno!))`
                `print("\(firstname!) \(lastname!), \(mobileno!)")`
            `}`
        `} catch let error as NSError {`
            `print ("Could not fetch. \(error), \(error.userInfo)")`
        `}`
        `return contactList`
    `}`

    `func updateContact(mobileno: String, newContact:Contact){`
        `let appDelegate = (UIApplication.shared.delegate) as! AppDelegate`
        `let context = appDelegate.persistentContainer.viewContext`
        `var contact:[NSManagedObject] = []`
        `let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "CDContact")`
        `do {`
            `contact = try context.fetch(fetchRequest)`

            `for c in contact {`
                `if (c.value(forKey: "mobileno") as? String == mobileno){`
                    `c.setValue(newContact.firstName, forKey: "firstname")`
                    `c.setValue(newContact.lastName, forKey: "lastname")`
                    `c.setValue(newContact.mobileNo, forKey: "mobileno")`
                `}`
            `}`
        `} catch let error as NSError {`
            `print ("Could not fetch. \(error), \(error.userInfo)")`
        `}`

        `do {`
            `try context.save()`
        `} catch let error as NSError {`
            `print ("Could not fetch. \(error), \(error.userInfo)")`
        `}`
    `}`

    `func deleteContact(mobileno: String){`
        `let appDelegate = (UIApplication.shared.delegate) as! AppDelegate`
        `let context = appDelegate.persistentContainer.viewContext`
        `var contact:[NSManagedObject] = []`
        `let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "CDContact")`
        `do {`
            `contact = try context.fetch(fetchRequest)`

            `for c in contact {`
                `if (c.value(forKey: "mobileno") as? String == mobileno){`
                    `context.delete(c)`
                `}`
            `}`
        `} catch let error as NSError {`
            `print ("Could not fetch. \(error), \(error.userInfo)")`
        `}`

        `do {`
            `try context.save()`
        `} catch let error as NSError {`
            `print ("Could not fetch. \(error), \(error.userInfo)")`
        `}`
    `}`