input: Write a function to create a class in Python to store and process data in a Car object. The class should have attributes for make, model, color, and mileage, and methods to accelerate and decelerate the car.
  assert Car("Toyota", "Camry", "Red", 5000).make=="Toyota"
  assert Car("Honda", "Civic", "Blue", 3000).model=="Civic"
  assert Car("Ford", "Mustang", "Black", 7000).color=="Black"
  assert Car("Tesla", "Model S", "White", 2000).mileage==2000
output: class Car:
      def __init__(self, make, model, color, mileage):
          self.make = make
          self.model = model
          self.color = color
          self.mileage = mileage
  
      def accelerate(self):
          self.mileage += 10
  
      def decelerate(self):
          self.mileage -= 10