using python to write a class for Car

I am trying to write a class for Car but I'm not getting the correct output. The brake data should subtract 5 from the speed data attribute each time it's called.

I tried the code below and the intended output for brake should be

brake 0: 20, brake1:15, brake2: 10, brake3:5 ,brake4:0

class Car:    def __init__(self,__year_model, __make):        self.__year_model = __year_model        self.__make = __make        self.__speed = 0    def accelerate(self):        self.__speed += 5    def brake(self):        self.__speed = -=5    def get_speed(self):        return self.__speed

from car import Carmy_car = Car("Corvette", 2022)for a in range(0,5):     b = my_car.accelerate()     speed = my_car.get_speed()     print(f"accelerate {a}: {speed}")print()for x in range(0,5):    ac = my_car.brake()    speed = my_car.get_speed()    print(f"brake {x}: {speed}")

output:

accelerate 0: 5accelerate 1: 10accelerate 2: 15accelerate 3: 20accelerate 4: 25brake 0: -5brake 1: -5brake 2: -5brake 3: -5brake 4: -5