由于缺少 python，apt 系统失败，但它就在那里

Question

尝试从 18.04 升级到 20.04 失败，导致系统崩溃，希望只有一个元素 - 系统无法识别 python，尽管我在 /usr/bin 中修补了 (符号链接)，因此“pythin --version”和“which python”可以工作。但 apt 失败了-

xxx@u9e16c415e3b459:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 alacarte : Depends: python:any (>= 2.7.5-5~)    
 ansible : Depends: python:any (< 2.8)
           Depends: python:any (>= 2.7~)
 autokey-common : Depends: python (< 2.8)
.................
.................

与修复损坏的尝试相同

xxxxx@u9e16c415e3b459:~$ sudo apt --fix-broken install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... failed.
The following packages have unmet dependencies:
 alacarte : Depends: python:any (>= 2.7.5-5~)    
 ansible : Depends: python:any (< 2.8)
           Depends: python:any (>= 2.7~)
.................
.................

xxxxx@u9e16c415e3b459:~$ which python
/usr/bin/python
xxxxx@u9e16c415e3b459:~$ python 
Python 3.6.9 (default, Jan 26 2021, 15:33:00) 
[GCC 8.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 

知道如何恢复吗？当然，重新安装 python 也会失败