diff --git a/.github/workflows/unittest.yaml b/.github/workflows/unittest.yaml
index 857bf894..66db384c 100644
--- a/.github/workflows/unittest.yaml
+++ b/.github/workflows/unittest.yaml
@@ -7,12 +7,17 @@ on:
 jobs:
   pytest-container:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.8','3.9','3.10','3.11','3.12']
 
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - name: checkout 
+        uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: ${{ matrix.python-version }}
           cache: "pip"
 
       - name: Install requirements
diff --git a/mace/calculators/mace.py b/mace/calculators/mace.py
index dcd2b8e5..0b801baf 100644
--- a/mace/calculators/mace.py
+++ b/mace/calculators/mace.py
@@ -8,7 +8,7 @@
 import logging
 from glob import glob
 from pathlib import Path
-from typing import Union
+from typing import List, Union
 
 import numpy as np
 import torch
@@ -51,7 +51,7 @@ class MACECalculator(Calculator):
     def __init__(
         self,
         model_paths: Union[list, str, None] = None,
-        models: Union[list[torch.nn.Module], torch.nn.Module, None] = None,
+        models: Union[List[torch.nn.Module], torch.nn.Module, None] = None,
         device: str = "cpu",
         energy_units_to_eV: float = 1.0,
         length_units_to_A: float = 1.0,