fix typing

jupyter_client/session.py

@@ -818,7 +818,7 @@ async def send_multipart(*args, **kwargs):
                 return await stream.send_multipart(*args, **kwargs)
 
             send_func = run_sync(send_multipart)
-        else:
+        elif stream is not None:
             send_func = stream.send_multipart
 
         if isinstance(msg_or_type, (Message, dict)):
@@ -861,7 +861,7 @@ async def send_multipart(*args, **kwargs):
         longest = max([len(s) for s in to_send])
         copy = longest < self.copy_threshold
 
-        if stream and buffers and track and not copy:
+        if stream is not None and buffers and track and not copy:
             # only really track when we are doing zero-copy buffers
             tracker = send_func(to_send, copy=False, track=True)
         elif stream:
@@ -914,10 +914,10 @@ def send_raw(
         to_send.append(self.sign(msg_list[0:4]))
         to_send.extend(msg_list)
         if isinstance(stream, zmq.asyncio.Socket):
-            assert stream is not None  # type:ignore[unreachable]
+            assert stream is not None
 
-            async def send_multipart(*args, **kwargs):
-                return await stream.send_multipart(*args, **kwargs)
+            async def send_multipart(*args: t.Any, **kwargs: t.Any) -> None:
+                await stream.send_multipart(*args, **kwargs)
 
             send_func = run_sync(send_multipart)
         else:
@@ -949,7 +949,7 @@ def recv(
 
         if isinstance(socket, zmq.asyncio.Socket):
 
-            async def recv_multipart(*args, **kwargs):
+            async def recv_multipart(*args: t.Any, **kwargs: t.Any) -> t.Any:
                 return await socket.recv_multipart(*args, **kwargs)
 
             recv_func = run_sync(recv_multipart)