How to access help for inner functions

How am I able to see what functions I can use under a certain graph library for e.g. I have been trying to fit a β€˜KDE’ line on the histogram I created but I do not how to. I assumed I will have to use go.Histogram(histnorm = dict(’’)) but I dont know how I can see what functions are available inside histnorm or any other function for that matter.
So how can I see what are the functions available in histnorm?

You can always see our handy Plotly Figure Reference Page.

See the section on Histograms here: