diff --git a/auton_survival/models/cph/dcph_utilities.py b/auton_survival/models/cph/dcph_utilities.py
index 6b2ca60..740ae48 100644
--- a/auton_survival/models/cph/dcph_utilities.py
+++ b/auton_survival/models/cph/dcph_utilities.py
@@ -10,6 +10,8 @@
 
 from auton_survival.models.dsm.utilities import get_optimizer, _reshape_tensor_with_nans
 
+from copy import deepcopy
+
 def randargmax(b,**kw):
   """ a random tie-breaking argmax"""
   return np.argmax(np.random.random(b.shape) * (b==b.max()), **kw)