accessing
asMessagesUserNamesSortedByOccurrences

	| response messagesOccurrences |
	messagesOccurrences := (self collect: [ :tweet | tweet user userName ]) asBag contents asDictionary.
	response := OrderedDictionary new.
	(messagesOccurrences associations asSortedCollection: [:x :y | x value > y value]) 
            collect: [:assoc | response at: assoc key put:assoc value].
	^ response