input: Write a function that takes two numbers as input, adds them together, and then doubles the result. Return the final result.
  def double_add(num1, num2): 
      return (num1 + num2) * 2
  
  assert double_add(2, 3) == 10
  assert double_add(-1, 1) == 0
  assert double_add(0, 0) == 0
  assert double_add(5, -5) == 0
  assert double_add(10, 10) == 40
output: def double_add(num1, num2): 
      return (num1 + num2) * 2