Just an FYI that hotpot still contains the now deprecated function get_context_instance().
These need to be changed to the new format context_xxxxxx::instance()
get_context_instance(CONTEXT_SYSTEM) turns into context_system::instance()
Thanks Matt. FYI, HotPot is designed to run on all versions of Moodle 2.x.
In Moodle >= 2.2, the calls to get_context_instance() are not used by HotPot.
However, in Moodle <= 2.1 the code *must* use get_context_instance().
That is why you found what you found.