That was initializer: ``` val v = listOf(TypeB("B1...

# getting-started

[ValV]

That was initializer:

val v = listOf(TypeB("B1", "A1"), TypeB("B2", "A2"), TypeB("B3", "A2")).groupBy { TypeA(it.a) }

And it was a Map<TypeA, List<TypeB>>, so I would like to:
1. separate initialization and population
2. make the map observable and mutable (to be able to add new items <key, value>)
3. make list mutable as well, to be able to add to list of values