diff --git a/outlines/caching.py b/outlines/caching.py
index 6fdda6214..83b91755e 100644
--- a/outlines/caching.py
+++ b/outlines/caching.py
@@ -126,7 +126,8 @@ def wrapper(*args, **kwargs):
 
         def __cache_key__(*args, **kwargs):
             """Make key for cache given function arguments."""
-            return args_to_key(base, args, kwargs, typed, ignore)
+            # return args_to_key(base, args, kwargs, typed, ignore)
+            return str(args_to_key(base, args, kwargs, typed, ignore))
 
         wrapper.__cache_key__ = __cache_key__  # type: ignore
         wrapper.__memory__ = memory  # type: ignore