bpo-37685: Fixed __eq__, __lt__ etc implementations in some classes. (GH-14952)

They now return NotImplemented for unsupported type of the other operand.
diff --git a/Tools/pynche/PyncheWidget.py b/Tools/pynche/PyncheWidget.py
index 364f22b..ef12198 100644
--- a/Tools/pynche/PyncheWidget.py
+++ b/Tools/pynche/PyncheWidget.py
@@ -281,10 +281,14 @@
         self.__window.deiconify()
 
     def __eq__(self, other):
-        return self.__menutext == other.__menutext
+        if isinstance(self, PopupViewer):
+            return self.__menutext == other.__menutext
+        return NotImplemented
 
     def __lt__(self, other):
-        return self.__menutext < other.__menutext
+        if isinstance(self, PopupViewer):
+            return self.__menutext < other.__menutext
+        return NotImplemented
 
 
 def make_view_popups(switchboard, root, extrapath):