Linux系统多Python版本时，pip如何指定版本安装软件

# 查看pip默认是安装到哪个版本的python
root@ubuntu:/home# pip -V
pip 20.3.4 from /usr/local/lib/python3.5/dist-packages/pip (python 3.5)
# 指定python版本安装
root@ubuntu:/home# pip install -t /usr/local/lib/python2.7/site-packages docker-py