input: Write a function to compute the sum of two variables and store the result in a third variable. The function should then print the result. If either of the input variables is not provided, the function should return None.
  def compute_sum_and_print(x=None, y=None):
      if x is None or y is None:
          return None
      result = x + y
      print(result)
      return result
  
  assert compute_sum_and_print(5, 8)==13
  assert compute_sum_and_print(0, 0)==0
  assert compute_sum_and_print(-5, 5)==0
  assert compute_sum_and_print() is None
  assert compute_sum_and_print(1) is None
output: def compute_sum_and_print(x=None, y=None):
      if x is None or y is None:
          return None
      result = x + y
      print(result)
      return result