Remove unreachable code for tornado 4

jupyter_server_proxy/websocket.py

@@ -7,7 +7,7 @@
 import inspect
 
 from jupyter_server.utils import ensure_async
-from tornado import httpclient, httputil, ioloop, version_info, websocket
+from tornado import httpclient, httputil, websocket
 
 
 class PingableWSClientConnection(websocket.WebSocketClientConnection):
@@ -40,31 +40,21 @@ def pingable_ws_connect(
     request.headers = httputil.HTTPHeaders(request.headers)
     request = httpclient._RequestProxy(request, httpclient.HTTPRequest._DEFAULTS)
 
-    # for tornado 4.5.x compatibility
-    if version_info[0] == 4:
-        conn = PingableWSClientConnection(
-            io_loop=ioloop.IOLoop.current(),
-            compression_options={},
-            request=request,
-            on_message_callback=on_message_callback,
-            on_ping_callback=on_ping_callback,
-        )
-    else:
-        # resolver= parameter requires tornado >= 6.3. Only pass it if needed
-        # (for Unix socket support), so older versions of tornado can still
-        # work otherwise.
-        kwargs = {"resolver": resolver} if resolver else {}
-        conn = PingableWSClientConnection(
-            request=request,
-            compression_options={},
-            on_message_callback=on_message_callback,
-            on_ping_callback=on_ping_callback,
-            max_message_size=getattr(
-                websocket, "_default_max_message_size", 10 * 1024 * 1024
-            ),
-            subprotocols=subprotocols,
-            **kwargs,
-        )
+    # resolver= parameter requires tornado >= 6.3. Only pass it if needed
+    # (for Unix socket support), so older versions of tornado can still
+    # work otherwise.
+    kwargs = {"resolver": resolver} if resolver else {}
+    conn = PingableWSClientConnection(
+        request=request,
+        compression_options={},
+        on_message_callback=on_message_callback,
+        on_ping_callback=on_ping_callback,
+        max_message_size=getattr(
+            websocket, "_default_max_message_size", 10 * 1024 * 1024
+        ),
+        subprotocols=subprotocols,
+        **kwargs,
+    )
 
     return conn.connect_future