diff --git a/gtsam/hybrid/hybrid.i b/gtsam/hybrid/hybrid.i
index bbee89733..dbc9bf5fe 100644
--- a/gtsam/hybrid/hybrid.i
+++ b/gtsam/hybrid/hybrid.i
@@ -158,10 +158,8 @@ class HybridBayesNet {
   gtsam::HybridValues optimize() const;
   gtsam::VectorValues optimize(const gtsam::DiscreteValues& assignment) const;
 
-  gtsam::HybridValues sample(const gtsam::HybridValues& given, std::mt19937_64@ rng) const;
-  gtsam::HybridValues sample(std::mt19937_64@ rng) const;
-  gtsam::HybridValues sample(const gtsam::HybridValues& given) const;
-  gtsam::HybridValues sample() const;
+  gtsam::HybridValues sample(const gtsam::HybridValues& given, std::mt19937_64@ rng = nullptr) const;
+  gtsam::HybridValues sample(std::mt19937_64@ rng = nullptr) const;
 
   void print(string s = "HybridBayesNet\n",
              const gtsam::KeyFormatter& keyFormatter =
diff --git a/gtsam/linear/linear.i b/gtsam/linear/linear.i
index 6ccac0902..dcd6c6f3f 100644
--- a/gtsam/linear/linear.i
+++ b/gtsam/linear/linear.i
@@ -560,10 +560,8 @@ virtual class GaussianConditional : gtsam::JacobianFactor {
       const gtsam::VectorValues& frontalValues) const;
   gtsam::JacobianFactor* likelihood(gtsam::Vector frontal) const;
 
-  gtsam::VectorValues sample(std::mt19937_64@ rng) const;
-  gtsam::VectorValues sample(const gtsam::VectorValues& parents, std::mt19937_64@ rng) const;
-  gtsam::VectorValues sample() const;
-  gtsam::VectorValues sample(const gtsam::VectorValues& parents) const;
+  gtsam::VectorValues sample(std::mt19937_64@ rng = nullptr) const;
+  gtsam::VectorValues sample(const gtsam::VectorValues& parents, std::mt19937_64@ rng = nullptr) const;
 
   // Advanced Interface
   gtsam::VectorValues solveOtherRHS(const gtsam::VectorValues& parents,