Python - Save data in a file when program ends

try the following code:

addressbook = []
class Parent:
    def Create(self):
        create_contact = input('''Please input the details of the contact you would like to create.
                           ''')
        addressbook.append(create_contact)
        print("Successfully added")
        return
    def Remove_contact(self):
        remove_contact = input('''Please input the details of the contact you would like to remove.
                            ''')
        if remove_contact in addressbook:
            print(addressbook.remove(remove_contact))
            print("Successfully removed contact.")
        else:
            print("Error", search_contact, "not found in the list")
        return
    def Search(self):
        search_contact = input('''Please input the details of the contact you would like to search for.
                            ''')
        if search_contact in addressbook:
            print(search_contact, "found in Address Book")
        else:
            print("Error", search_contact, "not found in the list")
        return
    def Display_contacts(self):
        print("Displaying contacts....", addressbook)
        return

def writeFile():
    with open("contact.txt",'a') as file:
        for contact in addressbook:
            file.write(str(contact)+"\n")

def loadFileContacts():
    with open("contact.txt",'r') as file:
        for contact in file:
            addressbook.append(contact)

def menu(parent):
    menu = input('''Address book to store friends contact
   -------------------------------------------------------------
   -------------------------------------------------------------
   Select an option...
   1 - Add/Update contact...
   2 - Display all contacts...
   3 - Search...
   4 - Delete contact...
   5 - Quit
    ''')

    if menu == '1':
        parent.Create()

    elif menu == '2':
        parent.Display_contacts()

    elif menu == '3':
        parent.Search()

    elif menu == '4':
        parent.Remove_contact()

    elif menu == '5':
        print("Quitting program")
        writeFile()
        quit()
    else:
        print("I did not understand that... Please try again")


p = Parent()
loadFileContacts()
print(addressbook)
while True:
    menu(p)