setupext.py 文件源码

def check(self):
        try:
            import six
        except ImportError:
            raise CheckFailed("six was not found.")

        if not is_min_version(six.__version__, self.min_version):
            return ("The installed version of six is {inst_ver} but "
                    "a the minimum required version is {min_ver}. "
                    "pip/easy install will attempt to install a "
                    "newer version."
                    ).format(min_ver=self.min_version,
                             inst_ver=six.__version__)

        return "using six version %s" % six.__version__