Scrap

locked_deque = RWLockSortedDeque(((('plc', i), f'data_{i}') for i in range(initial_size)),
locked_deque = RWLockSortedDeque(((('plc', i), f'data_{i}') for i in range(initial_size)),
                                 key=operator.itemgetter(0),
                                 maxlen=maxlen)
                                 maxlen=maxlen)
assert len(locked_deque) == initial_size

new_item = (('plc', initial_size + 1), 'new data')

with locked_deque.writer_lock() as writer:
with locked_deque.writer_lock() as writer:
    writer.append(new_item)
    writer.append(new_item)
assert len(locked_deque) == initial_size + 1

with locked_deque.reader_lock() as reader:
with locked_deque.reader_lock() as reader:
    # looking for the first element greater than all of those in the initial deque
    assert reader.find_gt(('plc', initial_size)) == new_item
    assert reader.find_gt(('plc', initial_size)) == new_item

the deque cannot exceed its maxlen

with locked_deque.writer_lock() as writer:
with locked_deque.writer_lock() as writer:
    for i in range(maxlen):
        new_item = (('plc', initial_size + 2 + i), 'new data')
        writer.append(new_item)
    assert len(locked_deque) == maxlen
    assert len(locked_deque) == maxlen

attempting to add another element, not larger than the previous one, will raise an error

with locked_deque.writer_lock() as writer:
with locked_deque.writer_lock() as writer:
    try:
        writer.append(new_item)
    except Exception as e:
        assert e == ValueError(f"Item key must be greater than last item key to append: {new_item[0]}")
    try:
        writer.append(new_item)
    except Exception as e:
        assert e == ValueError(f"Item key must be greater than last item key to append: {new_item[0]}")
    except Exception as e:
        assert e == ValueError(f"Item key must be greater than last item key to append: {new_item[0]}")
        assert e == ValueError(f"Item key must be greater than last item key to append: {new_item[0]}")