diff --git a/flopy/mf6/utils/codegen/dfn.py b/flopy/mf6/utils/codegen/dfn.py
index cbf527e84..f6d7c66e0 100644
--- a/flopy/mf6/utils/codegen/dfn.py
+++ b/flopy/mf6/utils/codegen/dfn.py
@@ -29,7 +29,7 @@
 Dfns = Dict[str, "Dfn"]
 
 
-def _try_parse_bool(value):
+def _try_parse_bool(value: Any) -> Any:
     """
     Try to parse a boolean from a string as represented
     in a DFN file, otherwise return the value unaltered.