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- **Removed**: Removed support for Python 2.
You have to upgrade to Python 3 if you want to use this version.
- Added support for Python 3.7 and 3.8 and PyPy 3.6.
- Make Python 3.7 the default testing environment.
- Upgrade Cerberus to version 1.3.2.
- Add integration for the Black code formatter.