diff --git a/fastapi/encoders.py b/fastapi/encoders.py
index 451ea0760..cc0d26a28 100644
--- a/fastapi/encoders.py
+++ b/fastapi/encoders.py
@@ -297,22 +297,20 @@ def jsonable_encoder(
                 encoded_dict[encoded_key] = encoded_value
         return encoded_dict
     if isinstance(obj, (list, set, frozenset, GeneratorType, tuple, deque)):
-        encoded_list = []
-        for item in obj:
-            encoded_list.append(
-                jsonable_encoder(
-                    item,
-                    include=include,
-                    exclude=exclude,
-                    by_alias=by_alias,
-                    exclude_unset=exclude_unset,
-                    exclude_defaults=exclude_defaults,
-                    exclude_none=exclude_none,
-                    custom_encoder=custom_encoder,
-                    sqlalchemy_safe=sqlalchemy_safe,
-                )
+        return [
+            jsonable_encoder(
+                item,
+                include=include,
+                exclude=exclude,
+                by_alias=by_alias,
+                exclude_unset=exclude_unset,
+                exclude_defaults=exclude_defaults,
+                exclude_none=exclude_none,
+                custom_encoder=custom_encoder,
+                sqlalchemy_safe=sqlalchemy_safe,
             )
-        return encoded_list
+            for item in obj
+        ]
 
     if type(obj) in ENCODERS_BY_TYPE:
         return ENCODERS_BY_TYPE[type(obj)](obj)
@@ -323,8 +321,7 @@ def jsonable_encoder(
     try:
         data = dict(obj)
     except Exception as e:
-        errors: List[Exception] = []
-        errors.append(e)
+        errors: List[Exception] = [e]
         try:
             data = vars(obj)
         except Exception as e: