diff --git a/python/boomer/common/cpp/rule_refinement.cpp b/python/boomer/common/cpp/rule_refinement.cpp
index c00a2a7ef2..4b5c9ada84 100644
--- a/python/boomer/common/cpp/rule_refinement.cpp
+++ b/python/boomer/common/cpp/rule_refinement.cpp
@@ -471,3 +471,17 @@ Refinement ExactRuleRefinementImpl::findRefinement(IHeadRefinement* headRefineme
 
     return refinement;
 }
+
+ApproximateRuleRefinementImpl::ApproximateRuleRefinementImpl(AbstractStatistics* statistics, BinArray* binArray,
+                                                             uint32 featureIndex) {
+    statistics_ = statistics;
+    binArray_ = binArray;
+    featureIndex_ = featureIndex;
+}
+
+Refinement ApproximateRuleRefinementImpl::findRefinement(IHeadRefinement* headRefinement,
+                                                         PredictionCandidate* currentHead,
+                                                         uint32 numLabelIndices, const uint32* labelIndices) {
+    Refinement refinement;
+    return refinement;
+}
diff --git a/python/boomer/common/cpp/rule_refinement.h b/python/boomer/common/cpp/rule_refinement.h
index 77a84fce66..9f11138483 100644
--- a/python/boomer/common/cpp/rule_refinement.h
+++ b/python/boomer/common/cpp/rule_refinement.h
@@ -110,4 +110,19 @@ class ExactRuleRefinementImpl : virtual public IRuleRefinement {
 
 class ApproximateRuleRefinementImpl : virtual public IRuleRefinement {
 
+    private:
+
+        AbstractStatistics* statistics_;
+
+        BinArray* binArray_;
+
+        uint32 featureIndex_;
+
+    public:
+
+        ApproximateRuleRefinementImpl(AbstractStatistics* statistics, BinArray* binArray, uint32 featureIndex);
+
+        Refinement findRefinement(IHeadRefinement* headRefinement, PredictionCandidate* currentHead,
+                                  uint32 numLabelIndices, const uint32* labelIndices) override;
+
 };