Changes from comments on PR ethereum#3116

Author: fselmo

docs/providers.rst

@@ -277,7 +277,7 @@ asynchronous context manager, can be found in the `websockets connection`_ docs.
         ...             if some_condition:
         ...                 # unsubscribe from new block headers and break out of
         ...                 # iterator
-        ...                 unsubscribed = await w3.eth.unsubscribe(subscription_id)
+        ...                 await w3.eth.unsubscribe(subscription_id)
         ...                 break
         ...
         ...         # still an open connection, make any other requests and get

web3/_utils/module_testing/persistent_connection_provider.py

@@ -292,7 +292,6 @@ async def test_async_eth_subscribe_mocked(
         expected_formatted_result: Any,
     ) -> None:
         sub_id = await async_w3.eth.subscribe(*subscription_params)
-        assert sub_id is not None
         assert is_hexstr(sub_id)
 
         async def _mocked_recv_coro() -> bytes: