prevent stats on dyn decks

aqt/main.py

@@ -662,6 +662,13 @@ upload, overwriting any changes either here or on AnkiWeb. Proceed?""")):
         deck = self._selectedDeck()
         if not deck:
             return
+        if deck['dyn']:
+            showInfo(_("""\
+As cards are removed from a filtered deck as they are answered, viewing the \
+statistics of a filtered deck will only show you reviews for cards with \
+multiple steps. To get an accurate report, please empty the filtered deck \
+and check the statistics for a home deck instead."""))
+            return
         aqt.stats.DeckStats(self)
 
     def onPrefs(self):