Andras Szalai added the comment:
What mislead me is:
The current code uses `is` and opposed to `==` which I assume is for the very
specific reason to match identity and not value.
The sentinel starts with a _, which to a casual reader (me) suggests that it's
a private implementation d
New submission from Andras Szalai:
In the class `logging.handlers.QueueListener` the `_sentinel` is `None`.
But
>>> a = None
>>> b = None
>>> a is b
True
Because of this, the QueueListener stops if it receives a `None`.
Were the sentinel a proper instance, like:
_se
