diff -r dc403312a012 -r 88472e743c64 hgext3rd/topic/stack.py
--- a/hgext3rd/topic/stack.py	Tue Aug 06 11:10:36 2019 +0200
+++ b/hgext3rd/topic/stack.py	Tue Aug 06 11:17:38 2019 +0200
@@ -317,7 +317,7 @@
 
         symbol = None
         states = []
-        if opts.get('children'):
+        if opts.get(b'children'):
             expr = 'children(%d) and merge() - %ld'
             revisions = repo.revs(expr, ctx.rev(), st._revs)
             if len(revisions) > 0: