diff --git a/tests/test_transforms.py b/tests/test_transforms.py
index eb0ee657..c363ceb5 100644
--- a/tests/test_transforms.py
+++ b/tests/test_transforms.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from collections import deque
+
 import pytz
 import numpy as np
 import pandas as pd