diff --git a/bleach/_vendor/html5lib/_trie/_base.py b/bleach/_vendor/html5lib/_trie/_base.py
index a1158bbb..6b71975f 100644
--- a/bleach/_vendor/html5lib/_trie/_base.py
+++ b/bleach/_vendor/html5lib/_trie/_base.py
@@ -1,6 +1,9 @@
 from __future__ import absolute_import, division, unicode_literals
 
-from collections import Mapping
+try:
+    from collections.abc import Mapping
+except ImportError:  # Python 2.7
+    from collections import Mapping
 
 
 class Trie(Mapping):