diff --git a/grain/_src/python/data_sources.py b/grain/_src/python/data_sources.py
index 7c9ad2957..6b45562be 100644
--- a/grain/_src/python/data_sources.py
+++ b/grain/_src/python/data_sources.py
@@ -21,6 +21,7 @@
 pipelines.
 """
 
+import abc
 import collections
 from collections.abc import Sequence
 import inspect