updated workflow to latest python version

Author: maddieamie

Diff for: .github/workflows/main.yml

@@ -15,15 +15,16 @@ jobs:
   ci:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Set up Python 3.9
-        uses: actions/setup-python@v2
+      - uses: actions/checkout@v3
+      - name: Set up Python
+        uses: actions/setup-python@v4
         with:
-          python-version: 3.9
+          python-version: 'latest'
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
           pip install -r requirements.txt
+
         working-directory: ./python
       - name: Test with pytest
         run: python3 -m pytest

Diff for: python/stack_queue_animal_shelter/stack_queue_animal_shelter.py

@@ -43,7 +43,7 @@ def reassign_queues(self):
         # Create a new queue for self.temp2
         self.temp_queue = Queue()
 
-    def dequeue_12(self, pref: str) -> None | str:
+    def dequeue_12(self, pref: str) -> Union['Animal'] | None | str:
         if self.shelter_queue.head is None:
             return "Animal Shelter queue is empty"