====== Install Python 3.8.2 for Windows 7 ======
----
===== - Install Package =====

==== - Download installation package. ====
From \\
https://www.python.org/ftp/python/3.8.2/python-3.8.2-amd64.exe \\
or \\
http://npm.taobao.org/mirrors/python/3.8.2/python-3.8.2-amd64.exe

==== - Install the software ====
you can: \\
Change the installation directory and chose some modules you like.

**<color #ed1c24>But, If you change de default installation directory, the following step 2.1 must be done.</color>**


After the installation finished, you can check it by run command : python -V
  D:\Python38>python -V
  Python 3.8.2

If there is something wrong with the PATH, you should set the PATH. or you can create a bat file with these commands.
  PATH = D:\Python38;D:\Python38\Scripts
Everytime you open a new command console, run this bat file first.


==== - Modify the site.py to configure pip environment ====
To check configuration, use command python -m site
  D:\Python38>python -m site
  sys.path = [
    'D:\\Python38',
    'D:\\Python38\\python38.zip',
    'D:\\Python38\\DLLs',
    'D:\\Python38\\lib',
    'D:\\Python38\\lib\\site-packages',
  ]
  USER_BASE: 'C:\\Users\\xxx\\AppData\\Roaming\\Python' (doesn't exist)
  USER_SITE: 'C:\\Users\\xxx\\AppData\\Roaming\\Python\\Python38\\site-packages' (doesn't exist)
  ENABLE_USER_SITE: True

It shows that USER_BASE and  USER_SITE are error.
modify file D:\Python38\Lib\site.py, change these two parameter to

  USER_SITE = "D:\Python38\Lib\site-packages"
  USER_BASE = "D:\Python38\Scripts"


check again: python -m site

==== - Reinstall pip ====

  python -m pip install --upgrade pip --force-reinstall
check pip by :
  D:\Python38>pip -V
  pip 20.0.2 from D:\Python38\Lib\site-packages\pip (python 3.8)     

===== - Embed Package =====
==== - Download Zip package and unzip ====
==== - 修改python38._pth ====
去掉#import site 前面的 “#” 注释
==== - 安装pip ====
  * 下载get-pip.py https://bootstrap.pypa.io/get-pip.py
  * 运行get-pip.py完成安装 (python get-pip.py)



===== Apendix =====
===== - For Python 3.8.8 =====
just install, revise the site.py and upgrede pip with:
  python -m pip install --upgrade pip
  
  
  -i https://pypi.tuna.tsinghua.edu.cn/simple