old_contents: """Logging configuration."""
  
  import logging
  
  __all__ = ['debug']
  
  logger = logging.getLogger(__package__)
  
  _debug_handler = None
  logger.addHandler(logging.NullHandler())
  
  def debug(dbg=True):
      """Enables or disables debugging messages on the standard output."""
      global _debug_handler
      if dbg and _debug_handler is None:
          _debug_handler = logging.StreamHandler()
          logger.addHandler(_debug_handler)
          logger.setLevel(logging.DEBUG)
      elif not dbg and _debug_handler is not None:
          logger.removeHandler(_debug_handler)
          _debug_handler = None
          logger.setLevel(logging.WARNING)
  
  
new_contents: """Logging configuration."""
  
  import logging
  
  __all__ = ['debug', 'logger']
  
  logger = logging.getLogger(__package__)
  
  _debug_handler = None
  logger.addHandler(logging.NullHandler())
  
  def debug(dbg=True):
      """Enables or disables debugging messages on the standard output."""
      global _debug_handler
      if dbg and _debug_handler is None:
          _debug_handler = logging.StreamHandler()
          logger.addHandler(_debug_handler)
          logger.setLevel(logging.DEBUG)
      elif not dbg and _debug_handler is not None:
          logger.removeHandler(_debug_handler)
          _debug_handler = None
          logger.setLevel(logging.WARNING)
  
  
subject: add logger to all imports