Writer error while _finalize_subscan

No idea if it is useful for.

This happens while the memory of my machine was evilly used by the BLISS shell.

ERROR 2021-01-29 15:36:33,617 nexus_writer_service.subscribers.session_writer: [demo_session-1 (ON)] [2_loopscan-1 (FAULT)] node None lacks initialization info
ERROR 2021-01-29 15:37:33,661 nexus_writer_service.subscribers.session_writer: [demo_session-1 (ON)] [2_loopscan-1 (FAULT)] Captured finalization exception:
Traceback (most recent call last):
  File "/users/valls/workspace/bliss.git/nexus_writer_service/subscribers/scan_writer_base.py", line 319, in _capture_finalize_exceptions
    yield
  File "/users/valls/workspace/bliss.git/nexus_writer_service/subscribers/scan_writer_base.py", line 873, in _finalize_subscan
    self._fetch_subscan_metadata(subscan)
  File "/users/valls/workspace/bliss.git/nexus_writer_service/subscribers/scan_writer_base.py", line 1827, in _fetch_subscan_metadata
    dataset = Dataset(self.node.parent)
  File "/users/valls/workspace/bliss.git/bliss/icat/dataset.py", line 24, in __init__
    super().__init__(node)
  File "/users/valls/workspace/bliss.git/bliss/icat/policy.py", line 27, in __init__
    node_type = node.type
AttributeError: 'NoneType' object has no attribute 'type'