docs: def should_skip_file(name):
      """
      Checks if a file should be skipped based on its name.
  
      If it should be skipped, returns the reason, otherwise returns
      None.
      """
      if name.endswith(('~', '.bak')):
          return 'Skipping backup file %(filename)s'
      if name.endswith(('.pyc', '.pyo')):
          return 'Skipping %s file ' % os.path.splitext(name)[1] + '%(filename)s'
      if name.endswith('$py.class'):
          return 'Skipping $py.class file %(filename)s'
      return None