Circumvent type issue

smartsim/entity/model.py

@@ -169,14 +169,16 @@ def attach_generator_files(
         # Check that no file collides with the parameter file written
         # by Generator. We check the basename, even though it is more
         # restrictive than what we need (but it avoids relative path issues)
-        if any(
-            osp.basename(filename) == "smartsim_params.txt"
-            for filename in list(itertools.chain(to_copy, to_symlink, to_configure))
-        ):
-            raise ValueError(
-                "`smartsim_params.txt` is a file automatically "
-                + "generated by SmartSim and cannot be ovewritten."
-            )
+        for strategy in [to_copy, to_symlink, to_configure]:
+            if strategy is not None and any(
+                osp.basename(filename) == "smartsim_params.txt"
+                for filename in strategy
+            ):
+                raise ValueError(
+                    "`smartsim_params.txt` is a file automatically "
+                    + "generated by SmartSim and cannot be ovewritten."
+                )
+
         self.files = EntityFiles(to_configure, to_copy, to_symlink)
 
     @property