I want to add to your advice: not all of your code has to live in Colab. If you create a public repo on GitHub, then on Colab you can simply do a pip install us

I want to add to your advice: not all of your code has to live in Colab. If you create a public repo on GitHub, then on Colab you can simply do a pip install using the git URI for your repo. Your GitHub repo will need to be setup as a proper Python library, but there are many simple examples you can find on the web. I find this technique to be particularly useful since the same GitHub based libraries that I use on Colab I sometimes also use from Common Lisp locally on my laptop using py4cl.