diff --git a/mlair/data_handler/input_bootstraps.py b/mlair/data_handler/input_bootstraps.py
index 2c0027f4df701a5e5956bc74fadbba11e7fafda5..287beea2d248d238fa34a68cf5311fa9d367dfa1 100644
--- a/mlair/data_handler/input_bootstraps.py
+++ b/mlair/data_handler/input_bootstraps.py
@@ -198,32 +198,17 @@ class BootstrapIteratorVariableSets(BootstrapIterator):
 
     @classmethod
     def create_collection(cls, data, dim):
-        # l = set()
-        # for i, x in enumerate(data.get_X(as_numpy=False)):
-        #     l.update(x.indexes[dim].to_list())
-        # # l.update(['O3Sect', 'O3SectLeft', 'O3SectRight']) # ToDo Remove : just for testing
-        # return [[var for var in to_list(l) if var.endswith(collection_name)] for collection_name in cls._variable_set_splitters]
-
         l = []
         for i, x in enumerate(data.get_X(as_numpy=False)):
             l.append(x.indexes[dim].to_list())
-        # l[0] = l[0] + ['o3Sect', 'o3SectLeft', 'o3SectRight', 'no2Sect', 'no2SectLeft', 'no2SectRight']
 
-        res = [[var for var in l[i] if var.endswith(collection_name)] for collection_name in cls._variable_set_splitters]
-        base_vars = [var for var in l[i] if not var.endswith(tuple(cls._variable_set_splitters))]
+        res = [[var for var in l[i] if var.endswith(collection_name)] for i, _ in enumerate(data.get_X(as_numpy=False))
+               for collection_name in cls._variable_set_splitters]
+        base_vars = [var for var in l[i] if not var.endswith(tuple(cls._variable_set_splitters)) for i, _ in
+                     enumerate(data.get_X(as_numpy=False))]
         res.append(base_vars)
         res = [(i, dimensions) for i, _ in enumerate(data.get_X(as_numpy=False)) for dimensions in res]
         return res
-        # return list(chain(*res))
-        # [[(0, 'o3'), (0, 'relhum'), (0, 'temp'), (0, 'u'), (0, 'v'), (0, 'no'), (0, 'no2'), (0, 'cloudcover'),
-        #    (0, 'pblheight')]]
-
-
-
-        # l = []
-        # for i, x in enumerate(data.get_X(as_numpy=False)):
-        #     l.append(list(map(lambda y: (i, y), x.indexes[dim])))
-        # return list(chain(*l))
 
 
 class ShuffleBootstraps: