Code optimizations wrt handling of None - bug 2212

svn: r10811

src/DisplayTabs/_ButtonTab.py

@@ -274,7 +274,7 @@ class ButtonTab(GrampsTab):
         # explicitly, dirty_selection must make sure they do not interact
         if self.dirty_selection:
             return
-        if self.get_selected() != None:
+        if self.get_selected() is not None:
             self.edit_btn.set_sensitive(True)
             if self.jump_btn:
                 self.jump_btn.set_sensitive(True)

src/DisplayTabs/_EmbeddedList.py

@@ -241,7 +241,7 @@ class EmbeddedList(ButtonTab):
 
     def _find_row(self, x, y):
         row = self.tree.get_path_at_pos(x, y)
-        if row == None:
+        if row is None:
             return len(self.get_data())
         else:
             return row[0][0]

src/DisplayTabs/_GalleryTab.py

@@ -203,7 +203,7 @@ class GalleryTab(ButtonTab):
     def _update_internal_list(self, *obj):
         newlist = []
         node = self.iconmodel.get_iter_first()
-        while node != None:
+        while node is not None:
             newlist.append(self.iconmodel.get_value(node, 2))
             node = self.iconmodel.iter_next(node)
         for i in xrange(len(self.media_list)):