def set_greenlet_uncaught_exception_handler(func):
global _uncaught_exception_handler<EOL>prev_handler, _uncaught_exception_handler = _uncaught_exception_handler, func<EOL>return prev_handler<EOL>
Sets a global greenlet uncaught exception handler that will get called if a greenlet spawned by one of this module's
wrappers raises an uncaught exception.
:param func: exception handler function that will receive the exc_info tuple as an argument
:returns: previous exception handler function or None