diff --git a/src/allmydata/immutable/upload.py b/src/allmydata/immutable/upload.py
index 1d70759ff..9d6842f44 100644
--- a/src/allmydata/immutable/upload.py
+++ b/src/allmydata/immutable/upload.py
@@ -2,22 +2,12 @@
 Ported to Python 3.
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
+from __future__ import annotations
 
-from future.utils import PY2, native_str
-if PY2:
-    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+from future.utils import native_str
 from past.builtins import long, unicode
 from six import ensure_str
 
-try:
-    from typing import List
-except ImportError:
-    pass
-
 import os, time, weakref, itertools
 
 import attr
@@ -915,8 +905,8 @@ class _Accum(object):
     :ivar remaining: The number of bytes still expected.
     :ivar ciphertext: The bytes accumulated so far.
     """
-    remaining = attr.ib(validator=attr.validators.instance_of(int)) # type: int
-    ciphertext = attr.ib(default=attr.Factory(list))                # type: List[bytes]
+    remaining : int = attr.ib(validator=attr.validators.instance_of(int))
+    ciphertext : list[bytes] = attr.ib(default=attr.Factory(list))
 
     def extend(self,
                size,           # type: int