r"""Log a string. It flushes but doesn't append \n, so do that yourself.

def _log(self, s):
    r"""Log a string. It flushes but doesn't append \n, so do that yourself."""
    # TODO(tewalds): Should this be using logging.info instead? How to see them
    # outside of google infrastructure?
    sys.stderr.write(s)
    sys.stderr.flush()