error messages for missing extra dependencies

[stes]

• #81
• Improve the ModuleNotFound error messages, and make them more actionable (e.g. directly suggest to install a particular set of extra deps, like datasets)

Original text

This solved it for me when I hit this error when working through the code in the Usage page.

A couple of notes (feel free to ignore 😄) -- I found the ModuleNotFound message a bit hard to interpret as it didn't say what module, so I wasn't sure how to proceed. Also, the installation page says that the datasets optional dependency is for working with the datasets at Figshare. Hence, when I got the error on the Usage page when trying to do stuff with synthetic data, I didn't consider the correct solution.

Anyway, minor wrinkles -- congrats on the cool package I'm having fun with it so far!
Originally posted by @EricThomson in #57 (comment)

[stes]

cc @gonlairo , this could be a small one to tackle --- basically just make the ModuleNotFound error messages in the package more actionable by telling the user what to install.