README.txt in amee-data-persistence-2.0.3 vs README.txt in amee-data-persistence-2.1.0

@@ -84,6 +84,9 @@
                                        :co2 => { :value => 234.1,
                                                  :unit => <Quantify::Unit::NonSI> }}
 
   my_calculation.save            #=> true
 
-  my_calculation.delete          #=> nil
+  my_calculation.delete          #=> nil
+
+n order to use the persistence library, prototype calculations must be held within
+instances of the AMEE::DataAbstraction::CalculationSet class
\ No newline at end of file