diff --git a/mapping_provider/backends/services.py b/mapping_provider/backends/services.py
index b07a896f50ecb819d681a325f04b1fa4da4ff70e..7406a0ebb29dbc150a2fd2297eb978aa22cd1a22 100644
--- a/mapping_provider/backends/services.py
+++ b/mapping_provider/backends/services.py
@@ -1,4 +1,3 @@
-import functools
 import logging
 import re
 from collections.abc import Generator
@@ -54,7 +53,9 @@ def endpoint_equipment(endpoint: dict[str, Any]) -> str:
     if 'hostname' in endpoint:
         return _hostname_to_equipment(endpoint['hostname'])
     elif 'equipment' in endpoint:
-        return endpoint['equipment']
+        _name = endpoint['equipment']
+        assert isinstance(_name, str)  # mypy noise
+        return _name
 
     # should already be validated
     raise AssertionError(f'no equipment or hostname in endpoint: {endpoint}')
diff --git a/test/test_map_endpoints.py b/test/test_map_endpoints.py
index 113fa37d7c8d2ecf902dc2b056b7b2214af24eea..c3dbaba94c42eed1fdaf0c348f7aa657bda64b87 100644
--- a/test/test_map_endpoints.py
+++ b/test/test_map_endpoints.py
@@ -76,7 +76,7 @@ def test_get_services(client, service_type):
 
 
 def test_get_unknown_service_type(client):
-    rv = client.get(f"/map/services/BOGUS_SERVICE_TYPE")
+    rv = client.get("/map/services/BOGUS_SERVICE_TYPE")
     assert rv.status_code == 404