Syntax cleanup `== None` -> `is None`
diff --git a/Lib/idlelib/PyShell.py b/Lib/idlelib/PyShell.py
index f8f7eef..271310a 100644
--- a/Lib/idlelib/PyShell.py
+++ b/Lib/idlelib/PyShell.py
@@ -350,7 +350,7 @@
     rpcpid = None
 
     def spawn_subprocess(self):
-        if self.subprocess_arglist == None:
+        if self.subprocess_arglist is None:
             self.subprocess_arglist = self.build_subprocess_arglist()
         args = self.subprocess_arglist
         self.rpcpid = os.spawnv(os.P_NOWAIT, sys.executable, args)