diff --git a/lib/sequencer/unit/import/common/model/statistics/diff/model_key.rb b/lib/sequencer/unit/import/common/model/statistics/diff/model_key.rb
index af31c7cc4..1474e8e80 100644
--- a/lib/sequencer/unit/import/common/model/statistics/diff/model_key.rb
+++ b/lib/sequencer/unit/import/common/model/statistics/diff/model_key.rb
@@ -20,6 +20,8 @@ class Sequencer
                   end
                 end
 
+                private
+
                 def model_key
                   model_class.name.pluralize.to_sym
                 end