diff --git a/examples/python/pyls_api.py b/examples/python/pyls_api.py
index 6659c75b70..240d6391a7 100644
--- a/examples/python/pyls_api.py
+++ b/examples/python/pyls_api.py
@@ -55,9 +55,23 @@ class SumFilter(pywrapcp.IntVarLocalSearchFilter):
 
   def OnSynchronize(self, delta):
     self.__sum = sum(self.Value(index) for index in range(self.Size()))
-      
+
   def Accept(self, delta, _):
-    return True
+    solution_delta = delta.IntVarContainer()
+    solution_delta_size = solution_delta.Size()
+    for i in range(solution_delta_size):
+      if not solution_delta.Element(i).Activated():
+        return True
+
+    new_sum = self.__sum
+    for i in range(solution_delta_size):
+      element = solution_delta.Element(index)
+      touched_var = self.FindIndex(element.Var())
+      old_value = self.Value(touched_var)
+      new_value = element.Value()
+      new_sum += new_value - old_value
+
+    return new_sum < self.__sum
 
   def IsIncremental(self):
     return False
@@ -85,7 +99,7 @@ def Solve(type):
     print 'Local Search with Filter'
     move_one_var = MoveOneVar(vars)
     sum_filter = SumFilter(vars)
-    ls_params = solver.LocalSearchPhaseParameters(move_one_var, db, None, 
+    ls_params = solver.LocalSearchPhaseParameters(move_one_var, db, None,
                                                   [sum_filter])
     ls = solver.LocalSearchPhase(vars, db, ls_params)
 
diff --git a/src/constraint_solver/python/constraint_solver.swig b/src/constraint_solver/python/constraint_solver.swig
index 165b7b0be2..cfec165e66 100644
--- a/src/constraint_solver/python/constraint_solver.swig
+++ b/src/constraint_solver/python/constraint_solver.swig
@@ -156,6 +156,7 @@ static bool PyCallbackBool(PyObject* pyfunc) {
 %feature("nodirector") operations_research::SequenceVarLocalSearchOperator::Start;
 %feature("director") operations_research::IntVarLocalSearchFilter;
 %feature("nodirector") operations_research::IntVarLocalSearchFilter::Start;
+%ignore operations_research::IntVarLocalSearchFilter::FindIndex;
 
 // We *do* need to use SWIGTYPE_... descriptor directly in embedded C++ code:
 // the recommended replacement $descriptor(...) is only available within
@@ -1119,6 +1120,14 @@ static void SetPythonFlags(bool trace_propagation,
     return self->Size();
   }
 }
+
+%extend IntVarLocalSearchFilter {
+  int FindIndex(IntVar* const var) {
+    index = -1;
+    self->FindIndex(var, &index);
+    return index;
+  }
+}
 }  // namespace operations_research
 
 // ############ BEGIN DUPLICATED CODE BLOCK ############