Fehler:
Odoo Server Error

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/fields.py", line 927, in __get__
    value = record.env.cache.get(record, self)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 967, in get
    value = self._data[key][field][record.id]
KeyError: 61

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 651, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 310, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/usr/lib/python3/dist-packages/odoo/tools/pycompat.py", line 87, in reraise
    raise value
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 693, in dispatch
    result = self._call_function(**self.params)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 342, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/service/model.py", line 97, in wrapper
    return f(dbname, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 335, in checked_call
    result = self.endpoint(*a, **kw)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 937, in __call__
    return self.method(*args, **kw)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 938, in call_button
    action = self._call_kw(model, method, args, {})
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 926, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 689, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 680, in call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/account/models/account_invoice.py", line 783, in action_invoice_open
    return to_open_invoices.invoice_validate()
  File "/mnt/extra-addons/membership_extension/models/account_invoice.py", line 61, in invoice_validate
    'date_cancel': refund.date_invoice,
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 3094, in write
    self._write(old_vals)
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 3322, in _write
    self.recompute()
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 4909, in recompute
    vals = {n: rec[n] for n in ns}
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 4909, in <dictcomp>
    vals = {n: rec[n] for n in ns}
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 4763, in __getitem__
    return self._fields[key].__get__(self, type(self))
  File "/usr/lib/python3/dist-packages/odoo/fields.py", line 931, in __get__
    self.determine_value(record)
  File "/usr/lib/python3/dist-packages/odoo/fields.py", line 1018, in determine_value
    self.compute_value(recs)
  File "/usr/lib/python3/dist-packages/odoo/fields.py", line 998, in compute_value
    self._compute_value(records)
  File "/usr/lib/python3/dist-packages/odoo/fields.py", line 989, in _compute_value
    getattr(records, self.compute)()
  File "/mnt/extra-addons/membership_extension/models/res_partner.py", line 138, in _compute_membership_date
    if not last_cancel or last_cancel < line.date_cancel:
TypeError: unorderable types: str() < bool()