diff --git a/server/protocol/protocol.py b/server/protocol/protocol.py
index d996b1455..e0f73d963 100644
--- a/server/protocol/protocol.py
+++ b/server/protocol/protocol.py
@@ -12,19 +12,19 @@
 
 class CustomJSONEncoder(json.JSONEncoder):
     # taken from https://stackoverflow.com/a/60243503
-    def encode(self, obj):
-        if isinstance(obj, Mapping):
+    def encode(self, o):
+        if isinstance(o, Mapping):
             dict_content = ", ".join(
                 f"{self.encode(key)}: {self.encode(value)}"
-                for (key, value) in obj.items()
+                for (key, value) in o.items()
             )
             return '{' + dict_content + '}'
-        elif isinstance(obj, Iterable) and not isinstance(obj, str):
-            return "[" + ", ".join(map(self.encode, obj)) + "]"
-        elif isinstance(obj, float):
-            return f"{obj:.{config.JSON_FLOAT_DIGITS_PRECISION}f}"
+        elif isinstance(o, Iterable) and not isinstance(o, str):
+            return "[" + ", ".join(map(self.encode, o)) + "]"
+        elif isinstance(o, float):
+            return f"{o:.{config.JSON_FLOAT_DIGITS_PRECISION}f}"
         else:
-            return super().encode(obj)
+            return super().encode(o)
 
 
 json_encoder = CustomJSONEncoder(separators=(",", ":"))