[Pharo-users] where are the nills come from and how do I get rid of them

Hello, I have to make a word count from a sentence so I did this : countWordsSentence: aString     | splitted result |     splitted := aString splitOn: [ :each | ', ' includes: each ].     result := splitted         inject: Bag new         into: [ :wordBag :word |             wordBag                 add: word;                 yourself ].     ^ result valuesAndCounts but now I see that the Bag is containing nills. I tried to delete them by doing this :   cleaned := result reject: [:each | each isNil] but to my surprise the nills are still there, Why is that happening and what is the best way to delete them ? Roelof