This patch is fixing an actual bug python-magnumclient, for example here when Horizon (openstack-dashboard) is deployed with magnum-dashboard on Focal/Ussuri the problem shows up when trying to list the cluster templates.

[Fri Jun 24 15:11:14.257350 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] error invoking apiclient
[Fri Jun 24 15:11:14.257388 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] Traceback (most recent call last):
[Fri Jun 24 15:11:14.257396 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/httpclient.py", line 409, in __iter__
[Fri Jun 24 15:11:14.257401 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     yield self.next()
[Fri Jun 24 15:11:14.257406 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/httpclient.py", line 421, in next
[Fri Jun 24 15:11:14.257411 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     raise StopIteration()
[Fri Jun 24 15:11:14.257433 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] StopIteration
[Fri Jun 24 15:11:14.257438 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] 
[Fri Jun 24 15:11:14.257442 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] The above exception was the direct cause of the following exception:
[Fri Jun 24 15:11:14.257447 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] 
[Fri Jun 24 15:11:14.257451 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] Traceback (most recent call last):
[Fri Jun 24 15:11:14.257456 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/openstack_dashboard/api/rest/utils.py", line 128, in _wrap
ped
[Fri Jun 24 15:11:14.257461 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     data = function(self, request, *args, **kw)
[Fri Jun 24 15:11:14.257465 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnum_ui/api/rest/magnum.py", line 71, in get
[Fri Jun 24 15:11:14.257470 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     result = magnum.cluster_template_list(request)
[Fri Jun 24 15:11:14.257475 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnum_ui/api/magnum.py", line 155, in cluster_template_li
st
[Fri Jun 24 15:11:14.257479 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     return magnumclient(request).cluster_templates.list(
[Fri Jun 24 15:11:14.257484 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/v1/basemodels.py", line 92, in list
[Fri Jun 24 15:11:14.257488 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     return self._list(self._path(path), self.__class__.api_name)
[Fri Jun 24 15:11:14.257493 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/base.py", line 121, in _list
[Fri Jun 24 15:11:14.257497 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     resp, body = self.api.json_request('GET', url)
[Fri Jun 24 15:11:14.257502 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/httpclient.py", line 233, in json_requ
est
[Fri Jun 24 15:11:14.257506 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     resp, body_iter = self._http_request(url, method, **kwargs)
[Fri Jun 24 15:11:14.257511 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/httpclient.py", line 201, in _http_req
uest
[Fri Jun 24 15:11:14.257515 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     body_list = [
[Fri Jun 24 15:11:14.257519 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]   File "/usr/lib/python3/dist-packages/magnumclient/common/httpclient.py", line 201, in <listcomp
>
[Fri Jun 24 15:11:14.257524 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284]     body_list = [
[Fri Jun 24 15:11:14.257529 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] RuntimeError: generator raised StopIteration
[Fri Jun 24 15:11:14.260524 2022] [wsgi:error] [pid 29641:tid 140291067918080] [remote 192.168.11.37:47284] Internal Server Error: /horizon/api/container_infra/cluster_templates/