diff -r c51fc0ae7a7e -r 12c8b24757f4 hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Wed Jul 03 11:13:47 2019 -0700
+++ b/hgext3rd/topic/__init__.py	Tue Jul 09 10:56:42 2019 -0700
@@ -626,14 +626,14 @@
 # revset predicates are automatically registered at loading via this symbol
 revsetpredicate = topicrevset.revsetpredicate
 
-@command('topics', [
-        ('', 'clear', False, 'clear active topic if any'),
-        ('r', 'rev', [], 'revset of existing revisions', _('REV')),
-        ('l', 'list', False, 'show the stack of changeset in the topic'),
-        ('', 'age', False, 'show when you last touched the topics'),
-        ('', 'current', None, 'display the current topic only'),
+@command(b'topics', [
+        (b'', b'clear', False, b'clear active topic if any'),
+        (b'r', b'rev', [], b'revset of existing revisions', _(b'REV')),
+        (b'l', b'list', False, b'show the stack of changeset in the topic'),
+        (b'', b'age', False, b'show when you last touched the topics'),
+        (b'', b'current', None, b'display the current topic only'),
     ] + commands.formatteropts,
-    _('hg topics [TOPIC]'))
+    _(b'hg topics [TOPIC]'))
 def topics(ui, repo, topic=None, **opts):
     """View current topic, set current topic, change topic for a set of revisions, or see all topics.