@NonNull static fun <A : Any!> concat(@NonNull left: MutableList<A>, @NonNull right: MutableList<A>): MutableList<A>
Concatenates two lists, adding elements of the second list at the end of the first list.
left - MutableList<A>: list ot be concatenated
right - MutableList<A>: list ot be concatenated
NullPointerException - if right is null
Return
MutableList<A>: new list, which contains elements of the first list and elements of the second list