use the optional None to prevent default list issue

bcipy/helpers/visualization.py

@@ -1,10 +1,8 @@
 # mypy: disable-error-code="attr-defined,union-attr"
 # needed for the ERPTransformParams
 import logging
-from typing import List, Optional, Tuple, Union
+from typing import List, Dict, Optional, Tuple, Union
 from pathlib import Path
-from pathlib import Path
-from typing import List, Dict, Optional, Tuple
 
 import matplotlib.pyplot as plt
 import mne
@@ -21,7 +19,6 @@
 from bcipy.config import (DEFAULT_DEVICE_SPEC_FILENAME, RAW_DATA_FILENAME,
                           STATIC_IMAGES_PATH, TRIGGER_FILENAME)
 from bcipy.helpers.acquisition import analysis_channels
-from bcipy.helpers.triggers import TriggerType, trigger_decoder
 from bcipy.helpers.parameters import Parameters
 from bcipy.helpers.convert import convert_to_mne
 from bcipy.helpers.load import choose_csv_file, load_raw_data

bcipy/main.py

@@ -1,7 +1,7 @@
 import argparse
 import logging
 import multiprocessing
-from typing import List
+from typing import List, Optional
 
 from psychopy import visual
 
@@ -183,7 +183,7 @@ def execute_task(
 def _clean_up_session(
         display: visual.Window,
         daq: ClientManager,
-        servers: List[LslDataServer] = []) -> bool:
+        servers: Optional[List[LslDataServer]] = None) -> bool:
     """Clean up session.
 
     Closes the display window and data acquisition objects. Returns True if the session was closed successfully.