- [ ] Consider all [Dafny standard library](https://github.com/dafny-lang/libraries/blob/master/src/Collections/Sequences/Seq.dfy) methods that mention (multi)sets in sequences - [ ] Consider axiomatization in [Gobra](https://github.com/viperproject/gobra/blob/9f38d64dc4dbc0dcad2de5d333200a8fd92bcb9d/src/main/scala/viper/gobra/translator/library/tos/SeqToSetImpl.scala#L12)
