diff --git a/README.md b/README.md
index 19637c4..ae323e4 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,7 @@ List
 ```python
 sum_of_elements  = sum(<collection>)
 elementwise_sum  = [sum(pair) for pair in zip(list_a, list_b)]
+cumulative_sum   = list(itertools.accumulate(<list>))
 sorted_by_second = sorted(<collection>, key=lambda el: el[1])
 sorted_by_both   = sorted(<collection>, key=lambda el: (el[1], el[0]))
 flatter_list     = list(itertools.chain.from_iterable(<list>))