Cannot load MachineVision Specification nodeset

[ghost]

Trying to open the MachineVision Specification (https://github.com/OPCFoundation/UA-Nodeset/tree/v1.04/MachineVision) gives the following error:

uawidgets.utils - ERROR - object of type 'ExtObj' has no len()')
Traceback (most recent call last):
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uawidgets\utils.py", line 21, in wrapper
    result = func(self, *args)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\uamodeler.py", line 249, in open
    self._model_mgr.open(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\model_manager.py", line 181, in open
    self.open_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\model_manager.py", line 113, in open_xml
    self._open_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\model_manager.py", line 119, in _open_xml
    path = self.import_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\model_manager.py", line 102, in import_xml
    new_nodes = self.server_mgr.import_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\server_manager.py", line 68, in import_xml
    return self._backend.import_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\uamodeler\server_manager.py", line 112, in import_xml
    return self._server.import_xml(path)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\opcua\server\server.py", line 510, in import_xml
    return importer.import_xml(path, xmlstring)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\opcua\common\xmlimporter.py", line 67, in import_xml
    node = self._add_node_data(nodedata)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\opcua\common\xmlimporter.py", line 88, in _add_node_data
    node = self.add_variable_type(nodedata)
  File "c:\users\appdata\local\programs\python\python38-32\lib\site-packages\opcua\common\xmlimporter.py", line 329, in add_variable_type
    if obj.value and len(obj.value) == 1:
TypeError: object of type 'ExtObj' has no len()