diff --git a/functionalpy/_sequence.py b/functionalpy/_sequence.py
index 9b9434a..65ba472 100644
--- a/functionalpy/_sequence.py
+++ b/functionalpy/_sequence.py
@@ -4,7 +4,6 @@
     Callable,
     Iterable,
     Iterator,
-    Mapping,
     Sequence,
 )
 from copy import deepcopy
diff --git a/functionalpy/benchmark/query_1/iterators_q1.py b/functionalpy/benchmark/query_1/iterators_q1.py
index 0734f4e..d7f84f7 100644
--- a/functionalpy/benchmark/query_1/iterators_q1.py
+++ b/functionalpy/benchmark/query_1/iterators_q1.py
@@ -105,7 +105,7 @@ def main_iterator(data: Sequence[Item]) -> Sequence[CategorySummary]:
 
     summaries = [
         summarise_category(group, rows=values)
-        for group, values in mapping.items()
+        for group, values in mapping.to_iter()
     ]
 
     return summaries