why isn’t the return type `ImmutableList`?

# getting-started

[stoyicker]

why isn’t the return type ImmutableList?

[miha-x64]

stoyicker: because there's no such interface in Kotlin. if (list !is MutableList) {, it is, probably, immutable. }

[stoyicker]

what does “probably” mean?

[voddan]

It means that implementation may be mutable, while the interface is read only

[voddan]

for example, listOf sometimes returns an immutable list, sometimes it returns an ArrayList, which is mutable, but still complies to read-only List