old_contents: 
  from pycket import config
  
  if not config.hidden_classes:
      from pycket.impersonators.hidden_classes import *
  else:
      from pycket.impersonators.baseline import *
  
new_contents: 
  from pycket import config
  
  if config.hidden_classes:
      from pycket.impersonators.hidden_classes import *
  else:
      from pycket.impersonators.baseline import *
  
subject: Use hidden classes by default