input: Write a function to generate a Python program that adds two numbers and then doubles the result.
  
  def double_add(num1, num2):
      return (num1 + num2) * 2
  
  assert double_add(3, 4) == 14
  assert double_add(-1, 1) == 0
  assert double_add(0, 0) == 0
  assert double_add(10, -5) == 10
  assert double_add(2, 2) == 8
output: def double_add(num1, num2):
      return (num1 + num2) * 2