Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
What if?
You put as value of an item in the passed array as an argument the number 12 for example.(It isn´t between 0 and 9)
Pass 9 or 11 elements or Array.Empty() on int[] numbers parameter.
Do these requirements return the expected value?
Semantically speaking, if the parameter is called "Friends" then you don't need to evaluate which are friends or not as the name of the function says, do you agree?