I don't think this needs an example, the issue is quite straightforward. While trying to pickle any datetime object containing a time zone created by dateutil:

TypeError: cannot pickle '_thread.lock' object

The object in question is:

datetime.datetime(2022, 11, 20, 17, 55, tzinfo=<tzicalvtz 'Europe/Rome'>

I understand why this happens: it's caused by the presence of this lock object.

class _tzicalvtz(_tzinfo):
    def __init__(self, tzid, comps=[]):
        super(_tzicalvtz, self).__init__()

        [...]
        self._cache_lock = _thread.allocate_lock()

I understand the presence of the lock itself (#428), can anybody suggest a way to fix this?

P.S. datetime instances are being created by niccokunzmann/python-recurring-ical-events.

Thanks for your help!