diff --git a/src/fsize/__init__.py b/src/fsize/__init__.py
index 979bf95..a979244 100644
--- a/src/fsize/__init__.py
+++ b/src/fsize/__init__.py
@@ -37,13 +37,13 @@
 
 import math
 import re
-from typing import Any, Self
+from typing import Any
 
 __all__ = ["FSize"]
 
 __version__ = "0.6.1"
 
-_UNIT_POWERS: dict[str, int] = {
+_UNIT_POWERS: "dict[str, int]" = {
     "B": 0,
     "K": 1,
     "M": 2,
@@ -67,7 +67,7 @@
 _MAX_FORMAT_WIDTH = 1000
 
 
-def _canonical_units(match: re.Match[str]) -> str:
+def _canonical_units(match: "re.Match[str]") -> str:
     """Return the canonical spelling of units matched by _RE_UNITS.
 
     Args:
@@ -90,7 +90,7 @@ class FSize(float):
 
     _convert: float
 
-    def __new__(cls, value: Any, units: str = "B") -> Self:
+    def __new__(cls, value: Any, units: str = "B") -> "FSize":
         """Create a new FSize instance.
 
         Create a new FSize instance, which is a subclass of float. The value is