UnboundLocalError: local variable 'nurNamen' referenced before assignment

[sentry-io]

Sentry Issue: FLASK-2

UnboundLocalError: local variable 'nurNamen' referenced before assignment
  File "flask\app.py", line 2077, in wsgi_app
    response = self.full_dispatch_request()
  File "flask\app.py", line 1525, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "flask\app.py", line 1523, in full_dispatch_request
    rv = self.dispatch_request()
  File "flask\app.py", line 1509, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "app.py", line 484, in spezielles_Dashboard
    nurNamen.append(name_line)  # append the name to the list