diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index 95fafff..72ea93e 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -33,7 +33,7 @@ jobs:
     - name: Lint with flake8
       strategy:
         matrix:
-          lint-directories: [./cdrhook, ./tests]
+          lint-directories: ["./cdrhook", "./tests"]
       run: |
         # stop the build if there are Python syntax errors or undefined names
         flake8 ${{ matrix.lint-directories }} --count --select=E9,F63,F7,F82 --show-source --statistics