input: Write a function to calculate the absolute difference between two given numbers. If either number is negative, the function should still return the absolute difference.
  
  def absolute_difference(A, B): 
      return abs(A - B) 
  
  assert absolute_difference(9, 5)==4
  assert absolute_difference(5, 9)==4  
  assert absolute_difference(10, -3)==13
  assert absolute_difference(-3, 10)==13
output: def absolute_difference(A, B): 
      return abs(A - B)