That resource is woefully outdated @sndselecta .
The magic install commands were added in 2019 to make it much easier to install packages from within the running notebook.
See here for more about the modern magic install commands.
You’ll see one of those listed resources, this one in particular, is by the author of Pythonic Permabulations suggesting the way added in 2019 is the improvement since that 2017 post you referenced.