diff --git a/gammapy/datasets/map.py b/gammapy/datasets/map.py
index 15d27518c2..d987246191 100644
--- a/gammapy/datasets/map.py
+++ b/gammapy/datasets/map.py
@@ -15,6 +15,7 @@
 from gammapy.stats import (
     CashCountsStatistic,
     WStatCountsStatistic,
+    cash,
     cash_sum_cython,
     get_wstat_mu_bkg,
     wstat,