diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 0000000..31671bd
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,2 @@
+[mypy]
+check_untyped_defs = True
diff --git a/repartir_taches/util.py b/repartir_taches/util.py
index 0fa51fe..8aa2fc8 100644
--- a/repartir_taches/util.py
+++ b/repartir_taches/util.py
@@ -29,7 +29,7 @@ def levenshtein_distance(s1, s2):
     if len(s1) > len(s2):
         s1, s2 = s2, s1
 
-    distances = range(len(s1) + 1)
+    distances: list[int] = list(range(len(s1) + 1))
     for i2, c2 in enumerate(s2):
         distances_ = [i2 + 1]
         for i1, c1 in enumerate(s1):