issubclass() arg 1 must be a class error when trying to retrieve zone

[Yannik]

Hi Erich,
thank you for creating this role!

Unfortunately, retrieving zones seems to be broken:

>>> from httpnet.client import HttpNetClient
>>> AUTH_TOKEN='my-auth-token'
>>> api = HttpNetClient(auth_token=AUTH_TOKEN)
>>>
>>> api.dns_zone_configs.get("my-zone-id")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/dns.py", line 106, in get
    return next(self.find(ZoneConfigId=key))
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 259, in find
    element = self._element_class.from_json(json_element)
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 140, in from_json
    fields[field] = _from_json_value(value, field_type)
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 88, in _from_json_value
    if issubclass(type_, Element):
TypeError: issubclass() arg 1 must be a class
>>>
>>> list(api.dns_zones.find())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 259, in find
    element = self._element_class.from_json(json_element)
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 140, in from_json
    fields[field] = _from_json_value(value, field_type)
  File "/home/yannik/.local/lib/python3.10/site-packages/httpnet/_core.py", line 88, in _from_json_value
    if issubclass(type_, Element):
TypeError: issubclass() arg 1 must be a class

It would be great if you could have a look at this :-)