What about something like:

   collection: aClass at: key do: aBlock
     | coll result |
     coll := self at: key ifAbsentPut: [aClass new].
     result := aBlock value: coll.
     coll ifEmpty: [self removeKey: key].
     ^ result

... perhaps with `ensure:` to do the removal?

Then:

   myDictOfSets collection: Set at: #key1 do: [:s | s add: 123].


On 3/26/21 8:17 PM, Marcel Taeumel wrote:
> ...