input: Write a function to create a class in Python to store and process data in a Car object with attributes for make, model, color, and mileage. The class should also include methods to accelerate and decelerate the car by a given speed.
  
  
  class Car:
      def __init__(self, make, model, color, mileage):
          self.make = make
          self.model = model
          self.color = color
          self.mileage = mileage
  
      def accelerate(self, speed):
          self.speed = speed
  
      def decelerate(self, speed):
          self.speed = speed
  
  
  assert Car("Toyota", "Corolla", "Red", 15000).make=="Toyota"
  assert Car("Toyota", "Corolla", "Red", 15000).model=="Corolla"
  assert Car("Toyota", "Corolla", "Red", 15000).color=="Red"
  assert Car("Toyota", "Corolla", "Red", 15000).mileage==15000
  my_car = Car("Toyota", "Corolla", "Red", 15000)
  my_car.accelerate(60)
  assert my_car.speed == 60
  my_car.decelerate(30)
  assert my_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
  