I think the use of SmallDictionaries for storing Famix state is not such a good idea. After loading the model: bag := Bag new . SmallDictionary allInstances do: [ :each | bag add: each size ]. bag sortedCounts "{530387->0. 19253->3. 18292->1. 20->2. 2->4. 2->11. 1->12}" bag := Bag new . SmallDictionary allInstances do: [ :each | bag add: (each keys) ]. bag sortedCounts an Array(530387->#() 19253->#(#cyclomaticComplexity #numberOfStatements #mooseName) 9311->#(#binding) 8707->#(#mooseName) 426->#(#comments) 20->#(#comments #ir) 13->#(#ir) 4->#(#comments #binding) 3->#(#binding #semanticWarning) 2->#('charset') 1->#(1 2 3 4 5 6 7 8 9 10 11 12) 1->#(14 15 16 17 18 19 20 21 22 23 24) 1->#(9 10 11 12 13 14 15 16) 1->an Array('-source-' #'`@method:' RBPatternVariableNode(`@args) '-pragmas-') 1->#(1 2 3 4 5 6 7 8 9 10 11) 1->{MooseModel} 1->{FAMIXAnnotationType. FAMIXClass. FAMIXNamespace. FAMIXMethod} 1->#(1 2))