[python2.7版本] pip安装包 或者 pip升级pip版本出现此错误：

······
      File "/tmp/pip-build-vD3Ntt/pip/setup.py", line 7
        def read(rel_path: str) -> str:
                         ^
    SyntaxError: invalid syntax
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-vD3Ntt/pip/
You are using pip version 8.1.2, however version 21.2.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

出现此错误后，执行升级pip和setuptools也出同样错误，网上搜索此错误解决方式都是升级pip和setuptools

原因呢肯定是pip问题了，解决办法：

# 本站下载 https://me.jinchuang.org/sofw/get-pip.zip
wget https://bootstrap.pypa.io/pip/2.7/get-pip.py
python get-pip.py
pip install --upgrade setuptools