При вызове аргумент функции выдает ошибку

number_served числового типа данных. При попытке его вывести с помощью new_restaurant.number_served() выдает ошибку, что невозможно вызвать int обьект.

class Restaurant:
    """Create easy restaurant model"""
    def __init__(self, restaurant_name, cuisine_type):
        """Create attributes"""
        self.restaurant_name = restaurant_name
        self.cuisine_type = cuisine_type
        self.number_served = 0

    def describe_restaurant(self):
        """Describe restaurant"""
        print(f"\nRestaurant name: {self.restaurant_name}.")
        print(f"Cuisine type: {self.cuisine_type}")

    def open_restaurant(self):
        """Say about restaurant open"""
        print(f"Restaurant {self.restaurant_name} status: open!")

    def closed_restaurant(self):
        """Say about restourant closed"""
        print(f"Restaurant {self.restaurant_name} status: closed!")

    def set_number_served(self, number):
        """Change number served"""
        self.number_served = (number)

    def incriment_number_served(self, number):
        """Incriment number served"""
        self.number_served += number

new_restaurant = Restaurant("Atomix", "Chinese")

new_restaurant.describe_restaurant()
new_restaurant.set_number_served(4)
new_restaurant.number_served()