Fixing my backup function

[Beginner_coder123]

Hello everyone, I'm trying to fix some methods such as "restore a backup" in my public library system.. But I've been stuck for weeks. Can someone help me out? The code is below, but it's a lot. Not that complicated to read, I hope. I basically expect to be able to make a book, and put it in my JSON file. I already have an existing JSON file, but it doesn't append it to file. But instead it keeps it in the dictionary I made it in, and when I run the "make backup" method, it appends it in my backed up file. How can I make it so that you can add a book straight into the JSON file that's being loaded? That is booklist.json

"""TODO:
Done - filling the system with books from a file of books in JSON format (file with books).  You may add a fake ISBN number to book items and generate the number of book items per book.
Done - filling the system with customers from a file of people ( file).
Done - adding a book item.
Done - adding a customer.
Done - searching a book.
Done - making a book loan.
Done - making a backup of the system in JSON format.
Not Done - restoring the system from a backup.
 """
 
 
import json
import csv
 
"""
    Created class 'Book' for adding a new book,
    Returning the new dict() back to the class 'bookItems'
    where it will be added to the bookcollection
"""
 
class Book:
    @staticmethod
    def createBook(FileBookcollection):
        #parameters is for the inputUser. So it shows the right text for the user
        parameters = ["author","country","imageLink","language","link","pages","title","year"]
        newBook = dict()
        for item in parameters:
            inputUser = input("Fill in the " + item + " of the book: ")
            if inputUser == "":
                newBook[item] = None
            else:
                #adding the parameters as key and inputUser as value to the dict newBook
                newBook[item] = inputUser
        #Adding ISBN to the Dict with a counter that counts the Len(Dict) + 1
        newBook["ISBN"] = str(len(FileBookcollection) + 1)
        return newBook
 
 

    def restoreBooksBackup(this):
        with open(r".\bookCollectionBackup.json") as jsonFile:
            bookList = json.load(jsonFile)
            this.JSONFileBookCollection = bookList

    def makeBackup(this):
        with open(r".\backupFakeNames.csv","w",newline="") as output:
            new_csv = csv.writer(output)
            new_csv.writerows(this.allPersonsInfo)
 
        with open(r".\bookCollectionBackup.json","w") as jsonFile:
            json.dump(this.bookCollection.getAllBooks(),jsonFile)
 
        with open(r".\loanbookListBackup.json","w") as jsonFile:
            json.dump(this.loanBookList,jsonFile)
 
    def restoreBackUp(this):
        pass
"""
        with open(r".\bookCollectionBackup.json") as jsonFile:
            bookList = json.load(jsonFile)
            this.bookCollection.dumbJSON.JSONFileBookCollection = bookList
        with open(r".\backupFakeNames.csv","r") as output:
            new_csv = csv.reader(output)
            totalPersonListBackup = []
            for line in new_csv:
                totalPersonListBackup.append(line)
        this.AllCustomers.allPersonsInfo.personsList = totalPersonListBackup
        #this.bookCollection.restoreBooksBackup()
        with open(r".\loanbookListBackup.json") as jsonFile:
            fileLoanBookBackup = json.load(jsonFile)
        this.loanBookList = fileLoanBookBackup
"""