如何在Colab中无需虚拟环境将Python降级至3.9？

问题背景 #

尝试将Colab默认Python3.10降级到3.9，按照某Stack Overflow步骤操作后，python3 --version显示3.9，但sys.version仍未改变，且执行以下命令时出现错误：

#install python 3.9 and dev utils
#you may not need all the dev libraries, but I haven't tested which aren't necessary.
!sudo apt-get update -y
!sudo apt-get install python3.9 python3.9-dev python3.9-distutils libpython3.9-dev

#change alternatives
!sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 1
!sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 2

#Check that it points at the right location
!python3 --version

# install pip
!curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
!python3 get-pip.py --force-reinstall

#install colab's dependencies
!python3 -m pip install ipython ipython_genutils ipykernel jupyter_console prompt_toolkit httplib2 astor

# link to the old google package
!ln -s /usr/local/lib/python3/dist-packages/google \
       /usr/local/lib/python3.9/dist-packages/google

# There has got to be a better way to do this...but there's a bad import in some of the colab files
# IPython no longer exposes traitlets like this, it's a separate package now
!sed -i "s/from IPython.utils import traitlets as _traitlets/import traitlets as _traitlets/" /usr/local/lib/python3.9/dist-packages/google/colab/*.py
!sed -i "s/from IPython.utils import traitlets/import traitlets/" /usr/local/lib/python3.9/dist-packages/google/colab/*.py

错误信息 #

执行上述命令后出现以下错误：

sed: can't read /usr/local/lib/python3.9/dist-packages/google/colab/*.py: No such file or directory
sed: can't read /usr/local/lib/python3.9/dist-packages/google/colab/*.py: No such file or directory

其他尝试的无效方法 #

• 执行!sudo update-alternatives --config python3，问题依旧
• 尝试将python3.9的dist-packages链接到旧版本，重启内核后Colab一直处于重连状态
• 创建Python3.9虚拟环境并更改Runtime Type，无法连接新内核

解决更新 #

2023年8月4日，按照某Stack Overflow回答中的方法操作后，问题在Colab中得以解决。

内容的提问来源于stack exchange，提问作者rfy1004