python3 安装 BeautifulSoup 报错

使用命令为 pip3 install BeautifulSoup4
错误信息为
Could not find a version that satisfies the requirement pip3 (from versions)
No matching distribution found for pip3
解决方案
首先升级pip
pip3 install --upgrade pip
再安装
pip3 install BeautifulSoup4
完美解决！