input: Write a function to add two numbers and then double the result. The function should return the doubled result of the sum of the two numbers.
  
  def double_add(num1, num2):
      return (num1 + num2) * 2
  
  assert double_add(3, 4) == 14
  assert double_add(0, 0) == 0
  assert double_add(-1, 1) == 0
  assert double_add(5, -3) == 4
  assert double_add(-2, -2) == -8
output: def double_add(num1, num2):
      return (num1 + num2) * 2