diff --git a/src/klein/_form.py b/src/klein/_form.py
index 6cdff819..8f09de91 100644
--- a/src/klein/_form.py
+++ b/src/klein/_form.py
@@ -267,7 +267,7 @@ def number(
         An integer within the range [minimum, maximum].
         """
 
-        def bounded_number(text: AnyStr) -> Any:
+        def bounded_number(text: str) -> Any:
             try:
                 value = kind(text)
             except (ValueError, ArithmeticError):