diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index cf59134..1956bd6 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,7 +2,7 @@ name: Integration Test
 
 on:
   pull_request:
-    branches: [TODO]
+    branches: [main2]
 
 jobs:
   do_test:
diff --git a/example.py b/example.py
index 7bcfc5b..60647dd 100644
--- a/example.py
+++ b/example.py
@@ -23,7 +23,7 @@ def difference(self):
         """
         Compute :math:`x - y`.
         """
-        #return self.y - self.x
+        return self.x - self.y
 
     def product(self):
         """