diff --git a/src/coinapi/utils/utils.py b/src/coinapi/utils/utils.py
index b74ee9e..11d32b3 100644
--- a/src/coinapi/utils/utils.py
+++ b/src/coinapi/utils/utils.py
@@ -848,7 +848,7 @@ def serialize(self, field_name: str, data: Any) -> dict[str, list[str]]:
 class StructFormDataSerializer(FormDataSerializer):
     """Serializer for Struct form data."""
 
-    def serialize(self, field_name: str, data: msgspec.Struct) -> dict[str, list[str]]:
+    def serialize(self, _field_name: str, data: msgspec.Struct) -> dict[str, list[str]]:
         """Serialize Struct form data."""
         form: dict[str, list[str]] = {}
         for field in msgspec.structs.fields(data):