diff --git a/assets/converters.py b/assets/converters.py
index 90ced6fe..da55d2e6 100644
--- a/assets/converters.py
+++ b/assets/converters.py
@@ -2,7 +2,7 @@ class AssetIDConverter:  # Forces lowercase to uppercase
     regex = '[^/]+'
 
     def to_python(self, value):
-        return value.upper()
+        return str(value).upper()
 
     def to_url(self, value):
-        return value.upper()
+        return str(value).upper()