diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 0e6182e..3b0a60a 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -39,4 +39,4 @@ jobs:
         pytest
     - name: Test with mypy
       run: |
-        mypy --strict sifter
+        mypy --strict sifter_extensions