Error while calling python function, TypeError: returnbook() missing 1 required positional argument: 'self'

I have created a python program where customers can return book and borrow book from Library, while executing I gets error * TypeError: borrow() missing 1 required positional argument: 'self' *

What changes I should make to execute the program successfully ?

I will call returnbook() function initially as the library have no books at present.

class Library:
    def __init__(self):
        self.availablebook = availablebook
    def reducebook(self,book):
        if book in self.availablebook:
            self.availablebook.remove(book)
            print('book is removed')
    def addbook(self,book):
        self.availablebook.append(book)
        print('book added')

class Customer:
    def borrow(self):
        print('enter book')
        book = input()
        Library.reducebook(book)
    def returnbook(self):
        print('enter book')
        book = input()
        Library.addbook(book)

while True:
    print('enter 1 for add book,2 for borrow book,3 to exit')
    self.x = int(input())
    if(x==1):
        Customer.borrow()
    elif(x==2):
        Customer.returnbook()
    else:
        print('exiting')
        quit()