diff --git a/app/brm/brn.py b/app/brm/brn.py
index c30f39c..9f0c88b 100644
--- a/app/brm/brn.py
+++ b/app/brm/brn.py
@@ -25,13 +25,13 @@ class BRN:
     global_namespace: str = field(default_factory=global_namespace)
 
     @classmethod
-    def from_str(cls, s: str) -> BRN:
-        parts = s.split(":")
+    def from_str(cls, string: str) -> BRN:
+        parts = string.split(":")
         if len(parts) != 6 or parts[0].lower() != "brn" or not is_integer(parts[2]):
-            raise TypeError(f"Expected a valid BRN but got {repr(s)} (invalid parts).")
+            raise TypeError(f"Expected a valid BRN but got {repr(string)} (invalid parts).")
         resource_parts = parts[5].split("/")
         if len(resource_parts) != 2:
-            raise TypeError(f"Expected a valid BRN but got {repr(s)} (invalid resource parts).")
+            raise TypeError(f"Expected a valid BRN but got {repr(string)} (invalid resource parts).")
         return cls(
             global_namespace=parts[1],
             group_id=int(parts[2]),
diff --git a/app/portal/list.py b/app/portal/list.py
index 2bc2af3..bf15128 100644
--- a/app/portal/list.py
+++ b/app/portal/list.py
@@ -20,18 +20,18 @@ bp = Blueprint("list", __name__)
 
 
 @bp.app_template_filter("provider_name")
-def list_provider_name(s: str) -> str:
-    return MirrorList.providers_supported.get(s, "Unknown")
+def list_provider_name(key: str) -> str:
+    return MirrorList.providers_supported.get(key, "Unknown")
 
 
 @bp.app_template_filter("format_name")
-def list_format_name(s: str) -> str:
-    return MirrorList.formats_supported.get(s, "Unknown")
+def list_format_name(key: str) -> str:
+    return MirrorList.formats_supported.get(key, "Unknown")
 
 
 @bp.app_template_filter("list_encoding_name")
-def list_encoding_name(s: str) -> str:
-    return MirrorList.encodings_supported.get(s, "Unknown")
+def list_encoding_name(key: str) -> str:
+    return MirrorList.encodings_supported.get(key, "Unknown")
 
 
 @bp.route('/list')