input: Write a function to create a class in Python that stores and processes data in a Car object. The class should have methods to accelerate and decelerate the car.
  
  
  class Car:
      def __init__(self, make, model, color, mileage):
          self.make = make
          self.model = self.model
          self.color = self.color
          self.mileage = self.mileage
  
      def accelerate(self, speed):
          self.speed = speed
  
      def decelerate(self, speed):
          self.speed = speed
  
  assert Car("Toyota", "Corolla", "Red", 5000).make == "Toyota"
  assert Car("Honda", "Civic", "Blue", 3000).model == "Civic"
  assert Car("Ford", "Mustang", "Yellow", 7000).color == "Yellow"
  assert Car("Chevrolet", "Malibu", "Green", 2000).mileage == 2000
  car = Car("Tesla", "Model S", "White", 10000)
  car.accelerate(70)
  assert car.speed == 70
  car.decelerate(30)
  assert car.speed == 30
  
output: 
  class Car:
      def __init__(self, make, model, color, mileage):
          self.make = make
          self.model = model
          self.color = color
          self.mileage = mileage
          self.speed = 0
  
      def accelerate(self, speed):
          self.speed += speed
  
      def decelerate(self, speed):
          self.speed -= speed
  