diff --git a/fastapi/encoders.py b/fastapi/encoders.py
index 45cdfd054..9f16fc5a0 100644
--- a/fastapi/encoders.py
+++ b/fastapi/encoders.py
@@ -1,6 +1,6 @@
 import dataclasses
 import datetime
-from collections import defaultdict, deque
+from collections import deque
 from decimal import Decimal
 from enum import Enum
 from ipaddress import (
@@ -14,7 +14,7 @@ from ipaddress import (
 from pathlib import Path, PurePath
 from re import Pattern
 from types import GeneratorType
-from typing import Any, Callable, Dict, Optional, Tuple, Type, Union
+from typing import Any, Callable, Dict, Optional, Type, Union
 from uuid import UUID
 
 from fastapi.types import IncEx