This is a Data subclass used to create pie charts. A pie chart can only
display one data series, and so this takes in a list of values and
labels directly unlike the Lines and Bars classes. Almost all
matplotlib pie chart keyword arguments are accepted, and information
about the plot legend should also be passed in, either upon creation
or set directly.

Pie.defaults shows a list of optional kwargs.

For further documentation see the following:
Data and Figures classes
https://github.com/HenryGinn/hgutilities
https://github.com/HenryGinn/hgutilities/tree/main/hgutilities/plotting
https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.pie.html
