input: Write a function to calculate and return the absolute difference between two given numbers. If either number is negative, the function should still return the positive 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(-5, 9)==14
  assert absolute_difference(9, -5)==14
  assert absolute_difference(0, 0)==0
output: def absolute_difference(A, B): 
      return abs(A - B)