Function hold

IPython/core/history.py:1112–1119

Context manger that hold a reference to a weak ref to make sure it is not GC'd during it's context.

(ref: ReferenceType[HistoryManager])

@contextmanager
def hold(ref: ReferenceType[HistoryManager]) -> Iterator[ReferenceType[HistoryManager]]:
    """
    Context manger that hold a reference to a weak ref to make sure it
    is not GC'd during it's context.
    """
    r = ref()
    yield ref
    del r


class HistorySavingThread(threading.Thread):