multiple inheritance to make protocols work

my/reddit/common.py

@@ -21,8 +21,6 @@ else:
 
 
 # common fields across all the Protocol classes, so generic code can be written
-# doesnt seem we can subclass this to the other Protocols though sadly, see
-# https://www.python.org/dev/peps/pep-0544/#toc-entry-28
 class RedditBase(Protocol):
     @property
     def raw(self) -> Json: ...
@@ -37,62 +35,23 @@ class RedditBase(Protocol):
 
 
 # Note: doesn't include GDPR Save's since they don't have the same metadata
-class Save(Protocol):
-    @property
-    def raw(self) -> Json: ...
-    @property
-    def created(self) -> datetime_aware: ...
-    @property
-    def id(self) -> str: ...
-    @property
-    def url(self) -> str: ...
-    @property
-    def text(self) -> str: ...
+class Save(Protocol, RedditBase):
     @property
     def subreddit(self) -> str: ...
 
 # Note: doesn't include GDPR Upvote's since they don't have the same metadata
-class Upvote(Protocol):
-    @property
-    def raw(self) -> Json: ...
-    @property
-    def id(self) -> str: ...
-    @property
-    def created(self) -> datetime_aware: ...
-    @property
-    def url(self) -> str: ...
-    @property
-    def text(self) -> str: ...
+class Upvote(Protocol, RedditBase):
     @property
     def title(self) -> str: ...
 
 
 # From rexport, pushshift and the reddit GDPR export
-class Comment(Protocol):
-    @property
-    def raw(self) -> Json: ...
-    @property
-    def id(self) -> str: ...
-    @property
-    def created(self) -> datetime_aware: ...
-    @property
-    def url(self) -> str: ...
-    @property
-    def text(self) -> str: ...
+class Comment(Protocol, RedditBase):
+    pass
 
 
 # From rexport and the GDPR export
-class Submission(Protocol):
-    @property
-    def raw(self) -> Json: ...
-    @property
-    def id(self) -> str: ...
-    @property
-    def created(self) -> datetime_aware: ...
-    @property
-    def url(self) -> str: ...
-    @property
-    def text(self) -> str: ...
+class Submission(Protocol, RedditBase):
     @property
     def title(self) -> str: ...