input: Write a function that creates a Python class named `Car` to store and process data in a Car object, including attributes like make, model, color, and mileage, and methods to manage speed by accelerating and decelerating.
  assert Car("Toyota", "Camry", "Blue", 50000).make == "Toyota"
  assert Car("Honda", "Civic", "Red", 30000).model == "Civic"
  assert Car("Ford", "Mustang", "Yellow", 20000).color == "Yellow"
  assert Car("Chevrolet", "Impala", "Black", 40000).mileage == 40000
  def Car(make, model, color, mileage):
      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
      return Car(make, model, color, mileage)
output: def Car(make, model, color, mileage):
      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
      return Car(make, model, color, mileage)