old_contents: """
  given a positive integer, return the next smallest and largest
  number with the same number of 1s in the binary represenation
  """
  
new_contents: """
  given a positive integer, return the next smallest and largest
  number with the same number of 1s in the binary represenation
  """
  # next higher int =  switch the lowest '1' with the next higher '0'
  # next lowest int =  switch the highest '0' with the next higher '1'
  
subject: Update 5.3_nextsmallbig.py