diff --git a/src/calibre/gui2/store/stores/mobileread/models.py b/src/calibre/gui2/store/stores/mobileread/models.py
index 5d4430cc6c..35a391074a 100644
--- a/src/calibre/gui2/store/stores/mobileread/models.py
+++ b/src/calibre/gui2/store/stores/mobileread/models.py
@@ -104,9 +104,7 @@ class BooksModel(QAbstractItemModel):
         if not self.books:
             return
         descending = order == Qt.SortOrder.DescendingOrder
-        self.books.sort(None,
-            lambda x: sort_key(type(u'')(self.data_as_text(x, col))),
-            descending)
+        self.books.sort(key=lambda x: sort_key(type(u'')(self.data_as_text(x, col))), reverse=descending)
         if reset:
             self.beginResetModel(), self.endResetModel()