types: CredentialsConfiguration.conf can return None

certbot-dns-linode/certbot_dns_linode/_internal/dns_linode.py

@@ -3,6 +3,7 @@ import logging
 import re
 from typing import Any
 from typing import Callable
+from typing import cast
 from typing import Optional
 from typing import Union
 
@@ -61,7 +62,7 @@ class Authenticator(dns_common.DNSAuthenticator):
     def _get_linode_client(self) -> '_LinodeLexiconClient':
         if not self.credentials:  # pragma: no cover
             raise errors.Error("Plugin has not been prepared.")
-        api_key = self.credentials.conf('key')
+        api_key = cast(str,self.credentials.conf('key'))
         api_version: Optional[Union[str, int]] = self.credentials.conf('version')
         if api_version == '':
             api_version = None