diff --git a/metcalcpy/sum_stat.py b/metcalcpy/sum_stat.py
index 65c02de1..1b7030db 100644
--- a/metcalcpy/sum_stat.py
+++ b/metcalcpy/sum_stat.py
@@ -37,6 +37,8 @@
 import time
 import logging
 import yaml
+import pandas as pd
+import warnings
 from inspect import signature
 
 from metcalcpy import GROUP_SEPARATOR