diff --git a/libcudacxx/test/utils/libcudacxx/test/config.py b/libcudacxx/test/utils/libcudacxx/test/config.py
index 1e186b6cd1b..55b048659c6 100644
--- a/libcudacxx/test/utils/libcudacxx/test/config.py
+++ b/libcudacxx/test/utils/libcudacxx/test/config.py
@@ -692,7 +692,7 @@ def configure_compile_flags(self):
 
                 # With Hopper there are new subarchitectures like 90a we need to handle those
                 subarchitecture = ''
-                if not isinstance(arch, int):
+                if not arch.isnumeric():
                     subarchitecture = arch[-1]
                     arch = arch[:-1]
                 arch = int(arch)