Sankey graph: 'NoneType' has no attribute 'descendants'

[pmiddend]

It's me again. I've tried passing cashdash my gnucash XML file. Some functionality works fine, but the Sankey graph isn't displayed. The log shows:

Traceback (most recent call last):
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2464, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2450, in wsgi_app
    response = self.handle_exception(e)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1867, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/dash/dash.py", line 1457, in dispatch
    response.set_data(self.callback_map[output]["callback"](*args))
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/dash/dash.py", line 1337, in add_context
    output_value = func(*args, **kwargs)  # %% callback invoked %%
  File "/home/philipp/projekte/cashdash/cashdash/dashes/cashflow.py", line 304, in update_figure
    for node in root_liability_node.descendants:
AttributeError: 'NoneType' object has no attribute 'descendants'

Maybe something about my gnucash file that you didn't have in your sample files? Can I somehow help, without giving you access to all my finances? :D

Edit: Putting an if root_liability_node is not None around the two for loops gives me a different error message (probably a follow-up error):

Traceback (most recent call last):
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2464, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2450, in wsgi_app
    response = self.handle_exception(e)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1867, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/dash/dash.py", line 1457, in dispatch
    response.set_data(self.callback_map[output]["callback"](*args))
  File "/home/philipp/projekte/cashdash/venv/lib/python3.8/site-packages/dash/dash.py", line 1337, in add_context
    output_value = func(*args, **kwargs)  # %% callback invoked %%
  File "/home/philipp/projekte/cashdash/cashdash/dashes/cashflow.py", line 353, in update_figure
    transaction_links = self.link_reconstructor.reconstruct(
  File "/home/philipp/projekte/cashdash/cashdash/algo/cvxpy_links.py", line 95, in reconstruct
    assert edges.value is not None
AssertionError