diff --git a/pyproject.toml b/pyproject.toml
index d89728e..49e3b29 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,8 @@ dependencies = [
   "jsonschema>=4.4.0",
   "fastjsonschema>=2.16.2",
   "raillabel>=3.1.0, <4.0.0",
-  "pyyaml>=6.0.0"
+  "pyyaml>=6.0.0",
+  "numpy>=1.24.4",
 ]
 
 [project.urls]
diff --git a/raillabel_providerkit/validation/validate_rail_side/validate_rail_side.py b/raillabel_providerkit/validation/validate_rail_side/validate_rail_side.py
index e791bd1..d01bd76 100644
--- a/raillabel_providerkit/validation/validate_rail_side/validate_rail_side.py
+++ b/raillabel_providerkit/validation/validate_rail_side/validate_rail_side.py
@@ -131,14 +131,14 @@ def _count_rails_per_track_in_frame(frame: raillabel.format.Frame) -> dict[str,
         left_count: int = 0
         right_count: int = 0
         for poly2d in poly2ds:
-            match poly2d.attributes["railSide"]:
-                case "leftRail":
-                    left_count += 1
-                case "rightRail":
-                    right_count += 1
-                case _:
-                    # NOTE: This is ignored because it is covered by validate_onthology
-                    continue
+            rail_side = poly2d.attributes["railSide"]
+            if rail_side == "leftRail":
+                left_count += 1
+            elif rail_side == "rightRail":
+                right_count += 1
+            else:
+                # NOTE: This is ignored because it is covered by validate_onthology
+                continue
 
         # Store counts of current track
         counts[object_uid] = (left_count, right_count)
diff --git a/tests/test_raillabel_providerkit/_util/test_filters.py b/tests/test_raillabel_providerkit/_util/test_filters.py
index b9bc5ab..c6c812b 100644
--- a/tests/test_raillabel_providerkit/_util/test_filters.py
+++ b/tests/test_raillabel_providerkit/_util/test_filters.py
@@ -1,6 +1,8 @@
 # Copyright DB Netz AG and contributors
 # SPDX-License-Identifier: Apache-2.0
 
+from __future__ import annotations
+
 import pytest
 import raillabel