input: Write a function to calculate the absolute difference between two given numbers. The function should return the absolute difference. If one or both numbers are not provided, the function should return 0.
  def absolute_difference(A, B): 
      if A is None or B is None:
          return 0
      return abs(A - B)
  
  # Test cases
  assert absolute_difference(9, 5) == 4
  assert absolute_difference(-10, 5) == 15
  assert absolute_difference(0, 0) == 0
  assert absolute_difference(None, 5) == 0
  assert absolute_difference(3, None) == 0
output: def absolute_difference(A, B): 
      if A is None or B is None:
          return 0
      return abs(A - B)