Plotly: subplots in figure (Part 2)

The caveat in Part 1 is about Pie chart: if one trying to replace any go.Bar or go.Histogram with go.Pie chart, there will be an error showing (plotly version 1.12.9) 

The reason for this is because the "tools.make_subplots" function creates a set of subplots based on different xaxis and yaxis, while go.Pie does not require (and it does not have) an axis property. 

The way to overcome such challenge is to build up the graph from scratch, using "domain" and "anchor".

To explain the concept, take a look at the "layout" in Part 1's example. Each layout axis (x and y) is attached with a specific domain on this figure, with its axis "anchored" with a specific data. subplot-1 is on upper left, so its xaxis domain is [0, 0.45] (left side), and yaxis domain is [0.625, 1] (upper side).

For Pie plot, since it cannot have axis, the make_subplots approach fake, but following approach still works

I have to say, I hate to use the Annotation as a way to make the subplot's title ... however, I currently didn't find any other way to directly assign subplot title. If you got any better approach to simplify the code in general, feel free to comment on this blog.