diff --git a/bitarray/__init__.pyi b/bitarray/__init__.pyi
index 10ca8294..05d9276a 100644
--- a/bitarray/__init__.pyi
+++ b/bitarray/__init__.pyi
@@ -108,7 +108,7 @@ class bitarray:
 
 
 class frozenbitarray(bitarray):
-    ...
+    def __hash__(self) -> int: ...
 
 
 def bits2bytes(n: int, /) -> int: ...
diff --git a/bitarray/util.pyi b/bitarray/util.pyi
index 79aab19c..0747a52a 100644
--- a/bitarray/util.pyi
+++ b/bitarray/util.pyi
@@ -1,4 +1,4 @@
-from typing import Any, AnyStr, BinaryIO, Literal, Optional, Union
+from typing import Any, AnyStr, BinaryIO, Hashable, Literal, Optional, Union
 
 from bitarray import bitarray
 
@@ -41,5 +41,5 @@ def int2ba(i: int, /,
 
 def serialize(a: bitarray, /) -> bytes: ...
 def deserialize(b: bytes, /) -> bitarray: ...
-def huffman_code(freq_map: dict[Any, Union[int, float]],
-                 endian: Optional[str] = ...) -> dict[Any, bitarray]: ...
+def huffman_code(freq_map: dict[Hashable, Union[int, float]],
+                 endian: Optional[str] = ...) -> dict[Hashable, bitarray]: ...