diff --git a/snippets/deep_flatten.md b/snippets/deep_flatten.md
index 349c1830d..7c6822bb3 100644
--- a/snippets/deep_flatten.md
+++ b/snippets/deep_flatten.md
@@ -10,6 +10,8 @@ Deep flattens a list.
 - If it is iterable, apply `deep_flatten()` recursively, otherwise return `[lst]`.
 
 ```py
+from collections.abc import Iterable
+
 def deep_flatten(lst):
   return ([a for i in lst for a in
           deep_flatten(i)] if isinstance(lst, Iterable) else [lst])