diff --git a/src/PriceListTools/PriceListTool.cs b/src/PriceListTools/PriceListTool.cs
index 5b10bf0..819bcc6 100644
--- a/src/PriceListTools/PriceListTool.cs
+++ b/src/PriceListTools/PriceListTool.cs
@@ -31,7 +31,7 @@ namespace RehauSku.PriceListTools
             }
         }
 
-        protected private void FillColumn(Dictionary<string, double> dictionary, int column)
+        protected private void FillColumn(IEnumerable<KeyValuePair<string, double>> dictionary, int column)
         {
             List<KeyValuePair<string, double>> missing = new List<KeyValuePair<string, double>>();