diff --git a/topobenchmarkx/data/dataloaders.py b/topobenchmarkx/data/dataloaders.py
index bddc1014..2578c4af 100755
--- a/topobenchmarkx/data/dataloaders.py
+++ b/topobenchmarkx/data/dataloaders.py
@@ -35,11 +35,10 @@ def to_data_list(batch):
             sparse_data = batch[key].coalesce()
             batch[key] = SparseTensor.from_torch_sparse_coo_tensor(sparse_data)
     data_list = batch.to_data_list()
-    
     for i, data in enumerate(data_list):
-        for key in data:
+        for key, d in data:
             if isinstance(data[key], SparseTensor):
-                data_list[i][key] = data[key].to_torch_sparse_coo_tensor()
+                data_list[i][key] = d.to_torch_sparse_coo_tensor()
     return data_list