code: def ensure_permissions(mode_flags=stat.S_IWUSR):
      
  
      def decorator(f):
          def modify(filename, *args, **kwargs):
              m = chmod_perms(filename) if exists(filename) else mode_flags
              if not m & mode_flags:
                  os.chmod(filename, m | mode_flags)
              try:
                  return f(filename, *args, **kwargs)
              finally:
                  # restore original permissions
                  if not m & mode_flags:
                      os.chmod(filename, m)
          return modify
  
      return decorator
docs: decorator to ensure a filename has given permissions.
  
      If changed, original permissions are restored after the decorated
      modification.