Backport of PEP 654 (exception groups)
"This is a backport of the BaseExceptionGroup and ExceptionGroup classes from Python 3.11. It contains the following: * The exceptiongroup.BaseExceptionGroup and exceptiongroup.ExceptionGroup classes * A utility function (exceptiongroup.catch()) for catching exceptions possibly nested in an exception group * Patches to the TracebackException class that properly formats exception groups (installed on import) * An exception hook that handles formatting of exception groups through TracebackException (installed on import) * Special versions of some of the functions from the traceback module"
