Update ariadne_codegen/contrib/client_forward_refs.py

Co-authored-by: DamianCzajkowski <[email protected]>

Author: bombsimon

ariadne_codegen/contrib/client_forward_refs.py

@@ -279,9 +279,7 @@ def _update_imports(self, module: ast.Module):
         # unless that's the type we return. This behaviour can differ if you use
         # a plugin such as `ShorterResultsPlugin` that will import a type that
         # is different from the type returned.
-        return_types_not_used_as_input.update(
-            {k for k in self.imported_in_method if k not in self.input_and_return_types}
-        )
+        return_types_not_used_as_input |= self.imported_in_method - self.input_and_return_types
 
         if len(return_types_not_used_as_input) == 0:
             return None