diff --git a/.github/workflows/test_vectors.yml b/.github/workflows/test_vectors.yml
index 9352782..e21c30c 100644
--- a/.github/workflows/test_vectors.yml
+++ b/.github/workflows/test_vectors.yml
@@ -27,9 +27,15 @@ jobs:
       - name: Install gnome-keyring
         run: sudo apt-get install gnome-keyring
 
+      - name: Install python 3.9
+        run: sudo apt-get install python3.9
+
       - name: Install poetry
         run: pip install --user poetry
 
+      - name: Set Python 3.9 as the version to use
+        run: poetry env use $(which python3.9)
+
       - name: Install dependencies
         run: poetry install --no-root