Merge pull request #301 from cwacek/fix/297

Attempt to resolve #297

Merge pull request #300 from cwacek/fix/292

Fix 292 by adding intermediary class builder.

Merge pull request #289 from MeggyCal/master

clear some Python 2 remnants (including six)

Merge pull request #283 from cwacek/fix/229

feature: Add support for the const keyword.

Merge pull request #279 from cwacek/fix/278

tests: Add a test to validate expected behavior on #278

Merge pull request #274 from cwacek/fix/referencing

bugfix: Update the way specifications are retrieved.

Merge pull request #266 from rmspeers/x-anyOf

Setup for handling anyOf simplifying to oneOf on import.

Merge pull request #264 from cwacek/fix/218

Migrate to jsonschema 4.18

Merge pull request #263 from cwacek/fix/218

bugfix: Fix #218 by serializing "null" for "null" types

Merge pull request #261 from azubieta/master

Handle float operation errors when using divmod