diff --git a/gtsam/discrete/DiscreteConditional.cpp b/gtsam/discrete/DiscreteConditional.cpp
index 78738dd54..055503b8e 100644
--- a/gtsam/discrete/DiscreteConditional.cpp
+++ b/gtsam/discrete/DiscreteConditional.cpp
@@ -484,7 +484,7 @@ double DiscreteConditional::evaluate(const Assignment<Key>& values) const {
 }
 
 /* ************************************************************************* */
-double DiscreteConditional::setData(const DiscreteConditional::shared_ptr& dc) {
+void DiscreteConditional::setData(const DiscreteConditional::shared_ptr& dc) {
   this->root_ = dc->root_;
 }