Plotly: How to make a line plot from a pandas dataframe with a long or wide format?

Question

(This is a self-answered post to help others shorten their answers to plotly questions by not having to explain how plotly best handles data of long and wide format)

Answer 1

I'm going to add this as answer so it will be on evidence. First of all thank you @vestland for this. It's a question that come over and over so it's good to have this addressed and it could be easier to flag duplicated question.

Plotly Express now accepts wide-form and mixed-form data as you can check in this post.