diff --git a/lib/rubella/output/ascii.rb b/lib/rubella/output/ascii.rb
index f4fe79e..514af0b 100644
--- a/lib/rubella/output/ascii.rb
+++ b/lib/rubella/output/ascii.rb
@@ -29,7 +29,8 @@ module Rubella
           @symbols.keys.join(", ")
       end
 
-      def create parsed_list
+      def create storage
+        parsed_list = storage.data
         buckets = parsed_list[0].length
         columns = parsed_list.length
 
diff --git a/lib/rubella/output/image.rb b/lib/rubella/output/image.rb
index cbae72a..a84fcb1 100644
--- a/lib/rubella/output/image.rb
+++ b/lib/rubella/output/image.rb
@@ -10,7 +10,8 @@ module Rubella
         @field_size = field_size
       end
 
-      def create parsed_list
+      def create storage
+        parsed_list = storage.data
         buckets = parsed_list[0].length
         columns = parsed_list.length
 
diff --git a/lib/rubella/weighting/per_value.rb b/lib/rubella/weighting/per_value.rb
index a86023c..3da46a0 100644
--- a/lib/rubella/weighting/per_value.rb
+++ b/lib/rubella/weighting/per_value.rb
@@ -23,7 +23,6 @@ module Rubella
 
         # total amount of cores
         total_amount = data[0].length
-        # TODO check somewhere, if every dataset has the same amount of cores
 
         # prepare data
         data_list = Array.new()
@@ -38,7 +37,7 @@ module Rubella
           end
         end
 
-        data_list
+        Rubella::Storage.new data_list
       end
       
     end