diff --git a/dynamic.py b/dynamic.py
index e302a840..684fed1a 100644
--- a/dynamic.py
+++ b/dynamic.py
@@ -144,8 +144,8 @@ def _check_array_additions(compare_array, module, is_list):
                 else:
                     result += evaluate.follow_call_list([second_param])
             elif add_name in ['extend', 'update']:
-                # TODO needs extensive work, because this are iterables
-                result += evaluate.follow_call_list(params)
+                iterators = evaluate.follow_call_list(params)
+                result += evaluate.handle_iterators(iterators)
         return result
 
     search_names = ['append', 'extend', 'insert'] if is_list else \
diff --git a/test/completion/dynamic.py b/test/completion/dynamic.py
index e3a5807b..082833f3 100644
--- a/test/completion/dynamic.py
+++ b/test/completion/dynamic.py
@@ -162,9 +162,14 @@ arr.extend([1,2,3])
 arr.extend([])
 arr.extend("")  # should ignore
 
-##? float() int()
-arr[0]
+#? float() int()
+arr[100]
 
+a = set(arr)
+a.update(list(["", 1]))
+
+#? float() int() str()
+list(a)[0]
 # -----------------
 # set/list initialized as functions
 # -----------------