input: Write a function to create a Python class named Car that stores and processes data related to a car object. The class should have an initializer method that takes make, model, color, and mileage as parameters and initializes the corresponding attributes. Additionally, the class should have methods to accelerate and decelerate the car by setting the speed attribute.
  
  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", "Camry", "Red", 5000).make=="Toyota"
  assert Car("Toyota", "Camry", "Red", 5000).model=="Camry"
  assert Car("Toyota", "Camry", "Red", 5000).color=="Red"
  assert Car("Toyota", "Camry", "Red", 5000).mileage==5000
  
  car = Car("Honda", "Civic", "Blue", 3000)
  car.accelerate(50)
  assert car.speed==50
  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