[AIT-289] fix: add python get_message_versions example

Author: ttypic

src/pages/docs/messages/updates-deletes.mdx

@@ -723,6 +723,17 @@ String serial = "0123456789-001@abcdefghij:001";
 PaginatedResult<Message> page = channel.getMessageVersions(serial);
 System.out.println("Found " + page.items().length + " versions");
 ```
+
+```python
+rest = AblyRest("{{API_KEY}}")
+channel = rest.channels.get("updates:example")
+
+# Example serial; for example from the `serial` property of a `Message` you previously received
+serial = "0123456789-001@abcdefghij:001"
+
+page = await channel.getMessageVersions(serial)
+print("Found " + len(page.items) + " versions");
+```
 </Code>
 
 ## Message version structure <a id="version-structure"/>