diff --git a/ortools/constraint_solver/python/constraint_solver.i b/ortools/constraint_solver/python/constraint_solver.i
index 69510d64f5..36790357f3 100644
--- a/ortools/constraint_solver/python/constraint_solver.i
+++ b/ortools/constraint_solver/python/constraint_solver.i
@@ -104,8 +104,10 @@ struct FailureProtect {
 // ============= Type conversions ==============
 
 // See ./constraint_solver_helpers.i
+PY_CONVERT_HELPER_PTR(Constraint);
 PY_CONVERT_HELPER_PTR(Decision);
 PY_CONVERT_HELPER_PTR(DecisionBuilder);
+PY_CONVERT_HELPER_PTR(Demon);
 PY_CONVERT_HELPER_PTR(SearchMonitor);
 PY_CONVERT_HELPER_PTR(IntervalVar);
 PY_CONVERT_HELPER_PTR(SequenceVar);
@@ -114,11 +116,17 @@ PY_CONVERT_HELPER_PTR(LocalSearchFilter);
 PY_CONVERT_HELPER_PTR(LocalSearchFilterManager);
 PY_CONVERT_HELPER_INTEXPR_AND_INTVAR();
 
+%{
+
+%}
+
 // Actual conversions. This also includes the conversion to std::vector<Class>.
 PY_CONVERT(IntVar);
 PY_CONVERT(IntExpr);
+PY_CONVERT(Constraint);
 PY_CONVERT(Decision);
 PY_CONVERT(DecisionBuilder);
+PY_CONVERT(Demon);
 PY_CONVERT(SearchMonitor);
 PY_CONVERT(IntervalVar);
 PY_CONVERT(SequenceVar);
@@ -603,6 +611,25 @@ PY_STRINGIFY_DEBUGSTRING(Decision);
   }
 }
 
+%extend operations_research::IntVarLocalSearchFilter {
+  int64_t IndexFromVar(IntVar* const var) const {
+    int64_t index = -1;
+    $self->FindIndex(var, &index);
+    return index;
+  }
+}
+
+// Extend IntVar to provide natural iteration over its domains.
+%extend operations_research::IntVar {
+  %pythoncode {
+  def DomainIterator(self):
+    return iter(self.DomainIteratorAux(False))
+
+  def HoleIterator(self):
+    return iter(self.HoleIteratorAux(False))
+  }  // %pythoncode
+}
+
 // Extend IntVarIterator to make it iterable in python.
 %extend operations_research::IntVarIterator {
   %pythoncode {
@@ -623,25 +650,6 @@ PY_STRINGIFY_DEBUGSTRING(Decision);
   }  // %pythoncode
 }
 
-// Extend IntVar to provide natural iteration over its domains.
-%extend operations_research::IntVar {
-  %pythoncode {
-  def DomainIterator(self):
-    return iter(self.DomainIteratorAux(False))
-
-  def HoleIterator(self):
-    return iter(self.HoleIteratorAux(False))
-  }  // %pythoncode
-}
-
-%extend operations_research::IntVarLocalSearchFilter {
-  int64_t IndexFromVar(IntVar* const var) const {
-    int64_t index = -1;
-    $self->FindIndex(var, &index);
-    return index;
-  }
-}
-
 // ############ BEGIN DUPLICATED CODE BLOCK ############
 // IMPORTANT: keep this code block in sync with the .i
 // files in ../java and ../csharp.
diff --git a/ortools/constraint_solver/python/pywrapcp_test.py b/ortools/constraint_solver/python/pywrapcp_test.py
index 4c4dede5fb..7f6d8c4a3e 100755
--- a/ortools/constraint_solver/python/pywrapcp_test.py
+++ b/ortools/constraint_solver/python/pywrapcp_test.py
@@ -576,10 +576,10 @@ def __init__(self, solver, x):
         print("Constraint built")
 
     def Post(self):
-        print("in Post()")
+        print("in Post()", file=sys.stderr)
         self._demon = CustomDemon(self._x)
         self._x.WhenBound(self._demon)
-        print("out of Post()")
+        print("out of Post()", file=sys.stderr)
 
     def InitialPropagate(self):
         print("in InitialPropagate()")
@@ -612,10 +612,10 @@ def Post(self):
     def InitialPropagate(self):
         if self._x.Bound():
             if self._x.Value() < 5:
-                print("Reject %d" % self._x.Value())
+                print("Reject %d" % self._x.Value(), file=sys.stderr)
                 self.solver().Fail()
             else:
-                print("Accept %d" % self._x.Value())
+                print("Accept %d" % self._x.Value(), file=sys.stderr)
 
 
 class WatchDomain(pywrapcp.PyDemon):
@@ -910,7 +910,6 @@ def solve(self, local_search_type):
             int_vars, solver.CHOOSE_FIRST_UNBOUND, solver.ASSIGN_MAX_VALUE
         )
         ls = None
-
         if local_search_type == 0:  # LNS
             print("Large Neighborhood Search")
             one_var_lns = self.OneVarLNS(int_vars)
@@ -939,6 +938,7 @@ def solve(self, local_search_type):
         print("Objective value = %d" % collector.ObjectiveValue(0))
 
     def test_large_neighborhood_search(self):
+        pass
         self.solve(0)
 
     def test_local_search(self):