diff --git a/Programs/_freeze_module.py b/Programs/_freeze_module.py
index 954aea7..90146b7 100644
--- a/Programs/_freeze_module.py
+++ b/Programs/_freeze_module.py
@@ -16,12 +16,14 @@ All function parameters must have type annotations.
 import inspect
 import marshal
 import sys
-from typing import TextIO, get_type_hints
+from typing import Any, Callable, TextIO, Type, TypeVar
 
 header: str = "/* Auto-generated by Programs/_freeze_module.py */"
 
+F = TypeVar('F', bound=Callable[..., Any])
 
-def strict_types(func):
+
+def strict_types(func: F) -> F:
     """Decorator that enforces type annotations on all parameters.
     
     Raises:
@@ -46,7 +48,7 @@ def strict_types(func):
     return func
 
 
-def _check_type(value, expected_type, param_name: str) -> None:
+def _check_type(value: Any, expected_type: Type, param_name: str) -> None:
     """Enforce strict type checking at runtime.
     
     Args: