* Move _syslog_facitily to __init__
No good reason it should not be set for each object
* Move internal property setting to private method
* Create check_arguments() function
* Remove unused import
* Rename function to better match its behavior
Change the behavior to return a set, either empty or populated, with unsupported keys.
Accept legal_inputs as optional which will not required calling handle_aliases before calling
get_unsupported_parameters().
* Add changelog
* Rework function behavior and documentation
I realized I missed the original intent of this method when moving it to a function. It
is meant to compared the parameter keys to legal inputs always, not compare
parameter keys to argument spec keys, even though the argument spec keys should
be a subset of legal inputs.
* Add tests
* Fix typo.
* Set internal properties when handling suboptions
