What is required for indexing with ranges? [Answered]

What exactly is required for indexing with a range (ex.

obj[..3]

obj[..3]

) to be supported on a class? Just having an indexer

public T this[int index]

public T this[int index]

causes a type error because you can't convert between a range and an int. I've know

Slice

Slice

exists and supposedly has something to do with range indexing, but I can't get it to work by just having a

public int Slice(int index, int length)

public int Slice(int index, int length)

method.