Filter Posts by Custom Taxonomy in Admin

A post on Pippin Williamson’s ‘Pippins Plugins’ site shows how to add a drop down to the WordPress admin to enable a custom post type list to be filtered by a custom taxonomy:

Here is how I used the function, with a fix for a possible isset notice suggested by Devin Price, in a plugin which includes taxonomies for ‘Role’ and ‘Location’ to display the posts in a ‘Team Members’ Custom Post Type.