code: def err(format_msg, *args, **kwargs):
      '''print format_msg to stderr'''
      exc_info = kwargs.pop("exc_info", False)
      stderr.warning(str(format_msg).format(*args, **kwargs), exc_info=exc_infof err(format_msg, *args, **kwargs):
      '''print format_msg to stderr'''
      exc_info = kwargs.pop("exc_info", False)
      stderr.warning(str(format_msg).format(*args, **kwargs), exc_info=exc_info)
docs: print format_msg to stderr